Deformation in volcanic areas: a numerical approach for their prediction in Teide volcano (Tenerife, Canary Islands); Deformaciones en areas volcanicas: una aproximacin numerica para su prediccion en el volcan Teide (Tenerife, Islas Canarias)

Energy Technology Data Exchange (ETDEWEB)

Charco, M.; Galan del Sastre, P.

2011-07-01

Active volcanic areas study comprises both, observation of physical changes in the natural media and the interpretation of such changes. Nowadays, the application of spatial geodetic techniques, such as GPS (Global Positioning System) or InSAR (Interferometry with Synthetic Aperture Radar), for deformation understanding in volcanic areas, revolutionizes our view of this geodetic signals. Deformation of the Earth's surface reflects tectonic, magmatic and hydrothermal processes at depth. In this way, the prediction of volcanic deformation through physical modelling provides a link between the observation and depth interior processes that could be crucial for volcanic hazards assessment. In this work, we develop a numerical model for elastic deformation study. The Finite Element Method (FEM) is used for the implementation of the numerical model. FEM allows to take into account different morphology, structural characteristics and the mechanical heterogeneities of the medium. Numerical simulations of deformation in Tenerife (Canary Islands) taking into account different medium hypothesis allow us to conclude that the accuracy of the predictions depends on how well the natural system is described. (Author) 22 refs.

Current Archaeological Research in Panamá Viejo, Panamá

OpenAIRE

Mendizábal, Tomás

1999-01-01

In late 1995 the government and private entities formed a pioneer organisation in Panamanian culture resource management, to deal with Panamá’s most salient archaeological site, Panamá Viejo. This association, the Patronato Panamá Viejo, was thus commissioned with the investigation and preservation of this 28-hectare site in the centre of modern Panamá City, as well as with keeping the community informed on the progress of the research. It is formed by four partners, the Instituto Nacional de...

Panamá Viejo: una experiencia exitosa de gestión patrimonial

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Juan Guillermo Martín

2013-04-01

Full Text Available Beginning in late 1995, the archaeological site of Panama Viejo was managed by Patronato Panama Viejo, a mixed, nonprofit organization whose main objectives focused on the protection, conservation, research and enhancement of the ruins of first Spanish port on the American Pacific coast. After more than fifteen years of work, the institution established the only permanent archaeological project in Panama, protected the site and its surroundings by passing a national law, and brokered, in 2003, its status as World Archaeological Heritage by Unesco. Such a task effectively involved specialists and various public and private sectors, in a joint effort that has become an example of cultural resources management at national and, probably, regional levels. Currently, Panama Viejo is one of the most visited tourist destinations in the country, surpassed only by the Panama Canal, and has established itself, as of 2010, as a regional center for archaeological research and specialized training.

Establecimientos incas en el subtramo Lampas – Pueblo Viejo en la región Ancash

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Bernabé Romero, Joseph A.

2015-01-01

Artículo sobre el registro de 5 asentamientos con componentes netamente Inca asociados al camino longitudinal de la sierra en el subtramo Lampas-Pueblo Viejo en Ancash. Entre los cuales destaca Pueblo Viejo (el de mayor extensión), pues presenta componentes del patrón de centros administrativos Inca.

Viejos y nuevos mitos

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ENRIQUE LUQUE

2001-01-01

Full Text Available El mito, desde la Grecia Antigua a los tiempos modernos, ha sido considerado como algo opuesto a la historia, la ciencia, la razón, e incluso, la vida cotidiana. De ese modo, el mito se equiparaba tanto a la sociedad antigua como a las sociedades primitivas. Sin embargo, hechos y procesos cruciales de la sociedades modernas y de la época industrial pueden verse con una nueva luz cuando se toma en cuenta el papel del mito, sea bajo viejos o nuevos ropajes. Además, lejos de ser un mero subproducto de la vida social, los mitos moldean en gran medida nuestra historia y nuestra sociedad.

Soil CO2 Degassing Path along Volcano-Tectonic Structures in the Pico-Faial-São Jorge Islands (Azores Archipelago, Portugal

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Fátima Viveiros

2017-06-01

Full Text Available The Azores archipelago is composed of nine volcanic islands located at the triple junction between the North American, Eurasian, and Nubian plates. Nowadays the volcanic activity in the archipelago is characterized by the presence of secondary manifestations of volcanism, such as hydrothermal fumaroles, thermal and cold CO2-rich springs as well as soil diffuse degassing areas, and low magnitude seismicity. Soil CO2 degassing (concentration and flux surveys have been performed at Pico, Faial, and São Jorge islands to identify possible diffuse degassing structures. Since the settlement of the Azores in the fifteenth Century these three islands were affected by seven onshore volcanic eruptions and at least six destructive earthquakes. These islands are crossed by numerous active tectonic structures with dominant WNW-ESE direction, and less abundant conjugate NNW-SSE trending faults. A total of 2,855 soil CO2 concentration measurements have been carried out with values varying from 0 to 20.7 vol.%. Soil CO2 flux measurements, using the accumulation chamber method, have also been performed at Pico and Faial islands in the summer of 2011 and values varied from absence of CO2 to 339 g m−2 d−1. The highest CO2 emissions were recorded at Faial Island and were associated with the Pedro Miguel graben faults, which seem to control the CO2 diffuse degassing and were interpreted as the pathways for the CO2 ascending from deep reservoirs to the surface. At São Jorge Island, four main degassing zones have been identified at the intersection of faults or associated to WNW-ESE tectonic structures. Four diffuse degassing structures were identified at Pico Island essentially where different faults intersect. Pico geomorphology is dominated by a 2,351 m high central volcano that presents several steam emissions at its summit. These emissions are located along a NW-SE fault and the highest measured soil CO2 concentration reached 7.6 vol.% with a maximum

Crust-Mantle Interactions at Pico de Orizaba (Citlaltepetl) Volcano, Mexico.

Science.gov (United States)

Schaaf, P.; Carrasco, G.

2006-12-01

Pico de Orizaba (Citlaltepetl) volcano constitutes the easternmost and highest stratovolcano of the subduction- related Plio-Quaternary Trans-Mexican Volcanic Belt (TMVB). The volcano can be divided into three main constructional stages. Its activity started during the mid-Pleistocene. The present cone was built on the remnants of the ancestral buildings by eruption of amphibole-two pyroxene dacitic lava flows, the most recent of which was erupted in the seventeenth century. The volcano is surrounded to the SW by monogenetic Quaternary cindercones and maars. All representative units were sampled in this work for geochemical and isotopic purposes, including a small quartzitic xenolith found in the basaltic monogenetic suite. Volcanic products of the stratocone are quite heterogeneous and range from calc-alkaline basaltic andesites to dome rhyolites, also displayed by a wide range of SiO2 and MgO (72.6-53.2 and 7.0-0.3 wt. %, respectively). In comparison to other TMVB stratovolcanoes (e.g., Colima, Nevado de Toluca), Pico de Orizaba shows similar 87Sr/86Sr ratios (0.7037-0.7048) but considerably more evolved Nd-Pb isotopic ratios (eNd: -1.8 to + 1.4; 206Pb/204Pb: 18.61-18.78). Elevated LILE concentrations and depleted HFSE witness the importance of slab- derived aqueous fluids and metasomatic reactions between the subducting lithosphere and overlying mantle wedge. On the other hand, Pico de Orizaba volcano shows additionally high crustal contributions of a source with depleted Sr and enriched Nd and Pb isotopic signatures, best explained by considerable assimilation of the local Grenvillian basement in magma generation processes. In contrast to Popocatépetl volcano with a high-level magma reservoir emplacement (7-8 km) and obvious interaction with the carbonate-dominated shallow basement rocks (e.g. elevated 87Sr/86Sr ratios and CO2 in gas plumes), this effect cannot be observed at Pico de Orizaba volcano, although a regional Cretaceous limestone basement is also

TAMBO VIEJO: UN ASENTAMIENTO FORTIFICADO EN EL VALLE DE ACARÍ, PERÚ (Tambo Viejo: A Fortified Settlement in the Acari Valley, Peru

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Lidio M. Valdez

2013-10-01

Full Text Available La aparición de los asentamientos fortificados y el origen del conflicto violento son temas poco discutidos en el contexto de la arqueología peruana. Considero que es oportuno investigar y determinar cuándo y por qué surgieron los primeros asentamientos fortificados. El propósito central de este artículo está precisamente orientado a responder tales interrogantes y discutir el tema del conflicto violento en el valle de Acarí y, por extensión, en la costa sur del Perú. Las evidencias arqueológicas disponibles señalan que, durante el periodo Intermedio Temprano, Tambo Viejo fue un asentamiento defendido por varias estructuras perimétricas. Otros sitios contemporáneos de Tambo Viejo en Acarí también fueron fortificados. Además, existe en el mismo valle evidencia tangible de violencia en la forma de prisioneros que posteriormente fueron decapitados. En contraste a la evidencia proveniente de Acarí, no existen asentamientos del periodo Intermedio Temprano identificables como fortificaciones, lo que hace de los sitios de Acarí los primeros asentamientos fortificados de toda la costa sur. ENGLISH: The emergence of violent conflict and of fortified settlements is a subject little studied within Peruvian archaeology. However, I consider it vital to investigate and determine the time and the reasons under which fortified settlements were first established. The central aim of this paper is to discuss when and why fortified settlements emerged first in the Acari Valley and, by extension, in the south coast of Peru. Available archaeological evidence indicates that during the Early Intermediate Period, Tambo Viejo was a fortified settlement protected by several massive walls. Other neighbouring sites in Acari were also fortified. Furthermore, in Acari there is conclusive evidence for violence in the form of decapitated individuals. In contrast to evidence coming from Acari, not a single Early Intermediate Period settlement from other

Volcanic crisis in

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Mgs. Víctor Manuel Pérez Martínez

2007-01-01

Full Text Available The article is the result of an investigation which is focussed on some deontological aspects of the scientificjournalism. In the first place it gives a theoretical vision about science, journalism, internet and including some reflectionsabout the deontological principles in handling the information about science and technology. This focus is useful as it formsthe base of an investigation where we deal with the information about a possible ”volcanic crisis” in El Teide during the years2004-2005 done by the digital newspaper” El Dïa” a canarian newspaper from Tenerife. The work required the revision of theinformation which was published and a followed analysis of its context. It was used the digital version with the purpose ofvisualizing the news which was published. It was also compared with a printed version, with local cover but divulged theinformation to the public who was most affected by this particular news. The results give rise to some questions regardinghow the information is given to a topic which is of local interest as well as national and international interest due to therepercussions in the social, economical and tourist field (the tourist field is the main industrial sector in Tenerife by receivingthis type of news.

Geoheritage value of the UNESCO site at Leon Viejo and Momotombo volcano, Nicaragua

Science.gov (United States)

van Wyk de Vries, Benjamin; Navarro, Martha; Espinoza, Eveling; Delgado, Hugo

2017-04-01

The Momotombo volcano has a special place in the history of Nicaragua. It is perfectly visible from the Capital, Managua, and from the major city of Leon. The old capital "Leon Viejo", founded in 1524 was abandoned in 1610, after a series of earthquakes and some major eruptions from Momotombo. The site was subsequently covered by Momotombo ash. A major geothermal power plant stands at the base of the volcano. Momotombo had been dormant for a hundred years, but had maintained high fumarole temperatures (900°C), indicating magma had been close to the surface for decades. In recent years, seismic activity has increased around the volcano. In December 2015, after a short ash eruption phase the volcano erupted lava, then a string of Vulcanian explosions. The volcano is now in a phase of small Vulcanian explosions and degassing. The Leon Viejo World Heritage site is at risk to mainly ash fall from the volcano, but the abandonment of the old city was primarily due to earthquakes. Additional risks come from high rainfall during hurricanes. There is an obvious link between the cultural site (inscribed under UNESCO cultural criteria) and the geological environment. First, the reactivation of Momotombo volcano makes it more important to revise the hazard of the site. At the same time, Leon Viejo can provide a portal for outreach related to the volcano and for geological risk in general. To maximise this, we provide a geosite inventory of the main features of Momotombo, and it's environs, that can be used as the first base for such studies. The volcano was visited by many adventure tourists before the 2015/2016 eruption, but is out of bounds at present. Alternative routes, around the volcano could be made, to adapt to the new situation and to show to visitors more of the geodiversity of this fascinating volcano-tectonic and cultural area.

Monitoring diffuse He degassing from the summit crater of Pico do Fogo volcano, Cape Verde

Science.gov (United States)

Alonso, Mar; Dionis, Samara; Fernandes, Paulo; Melián, Gladys; Asensio-Ramos, María; Padilla, Germán D.; Hernández, Pedro A.; Pérez, Nemesio M.; Silva, Sonia

2017-04-01

Fogo (476km2) is one of the Sotavento islands of Cape Verde archipelago. The main geomorphological feature is the presence of a 9 km wide caldera hosting one of the world's most active volcanoes, Pico do Fogo (2829 m.a.s.l.), with the last eruption occurring on November 2014. Pico do Fogo volcano is characterized by the existence of a fumarolic field situated NW inside the summit crater and composed by low- and high-temperature gas discharges (90 to above 200oC respectively) with widespread sulfur precipitates at the surface, typical of hydrothermal alteration. As part of the geochemical monitoring program for the volcanic surveillance of Fogo volcano, twelve surveys of diffuse Helium (He) emission through the surface of the crater have been performed since 2008. He emission has been measured because it is considered as an excellent geochemical indicator (Pogorsky and Quirt 1981) due to its geochemical properties. Recent results clearly show the importance of helium emission studies for the prediction of major volcanic events and the importance of continuous monitoring of this gas in active volcanic regions (Padrón et al. 2013). Soil He emission rates were measured always at the same 63 sampling sites distributed inside the crater and covering an area of 0.142km2. At each measurement site, soil gas was collected in 10 cc glass vials with a hypodermic syringe by inserting to 40 cm depth a 50 cm stainless probe and later analyzed for He content by a quadrupole mass spectrometer Pfeiffer Omnistar 422. Diffusive and convective emission values were estimated at each sampling site following the Fick and Darcy's laws. The He emission rate through the crater was estimated after making the spatial interpolation maps using sequential Gaussian simulation. The average emission rate during these eight years of study is 3.3 kg d-1. The emission rate showed an important increase (up to 5.7 kg d-1) eight months before the 2014 eruption onset. During the eruptive period the crater

Changes in Al and Fe associated with amorphous soil minerals over one year after a wildfire at Pico Cho Marcial (Tenerife, Canary Islands, Spain

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J. Notario

2013-05-01

Full Text Available Amorphous-linked Al, Fe and Si were determined both in burned and unburnt soil samples after a wildfire close to Pico Cho Marcial (Tenerife, Canary Islands, Spain that affected 7.1 ha of high mountain Teide broom scrub along four successive samplings held in September 2003 (three months after the wildfire, February 2004, June 2004 and October 2004. Soils in the area are Lithic Xerorthents, with a scarcely developed AC-type profile. The chemical elements under study were extracted using selective dissolutions (0.2M acid ammonium oxalate and 0.1N sodium pyrophosphate, and determined by Atomic Absorption Spectrophotometry. The average contents of total amorphous Al (oxalate-extractable and organo-metallic complexes-bound Al (pyrophosphate extractable were significantly higher in burned samples along the study. Also, the oxalate-extractable Al varied significantly along the different samplings, and so consequently did the Alp:Alox ratio. A progressive decrease in the Al:Si ratio in allophanes was also found throughout the study period. No differences were found for oxalate-extractable Fe, either between sample groups or samplings, which was also applicable to the (Alox+0.5Feox percentage.

Age progressive volcanism opposite Nazca plate motion: Insights from seamounts on the northeastern margin of the Galapagos Platform

Science.gov (United States)

Sinton, Christopher W.; Hauff, Folkmar; Hoernle, Kaj; Werner, Reinhard

2018-06-01

We present new geochemical and 40Ar/39Ar analyses from seven seamounts located off the northeastern margin of the shallow Galápagos Platform. Initial volcanism at 5.2 Ma created a small island (Pico) over the current location of the hotspot with geochemically enriched lavas. There is no further record of magmatism in the study area until 3.8 to 2.5 Ma, during which four roughly conical volcanoes (Sunray, Grande, Fitzroy, and Beagle) formed through eruption of lavas derived from a depleted mantle source. Sunray, Fitzroy, and Grande were islands that existed for 3 m.y. ending with the submergence of Fitzroy at 0.5 Ma. The youngest seamounts, Largo and Iguana, do not appear to have been subaerial and were active at 1.3 Ma and 0.5 Ma, respectively, with the style of edifice changing from the previous large cones to E-W elongate, composite structures. The progression of magmatism suggests that Pico erupted near 91.5°W near the location of the Galápagos plume while the others formed well east of the plume center. If the locations of initial volcanism are calculated using the eastward velocity of the Nazca plate, there appears to be a progression of younger volcanism toward the east, opposite what would be expected from a fixed mantle plume source. The rate that initial volcanism moves eastward is close to the plate velocity. A combination of higher temperature and geochemical enrichment of the thickened lithosphere of the Galápagos platform could have provided a viscosity gradient at the boundary between the thick lithosphere and the thinner oceanic lithosphere to the northeast. As this boundary moved eastward with the Nazca plate, it progressively triggered shear-driven mantle upwelling and volcanism.

The bulk isotopic composition of hydrocarbons in subaerial volcanic-hydrothermal emissions from different tectonic settings

Science.gov (United States)

Fiebig, J.; Tassi, F.; Vaselli, O.; Viveiros, M. F.; Silva, C.; Lopez, T. M.; D'Alessandro, W.; Stefansson, A.

2015-12-01

Assuming that methane and its higher chain homologues derive from a common source, carbon isotope patterns have been applied as a criterion to identify occurrences of abiogenic hydrocarbons. Based on these, it has been postulated that abiogenic hydrocarbon production occurs within several (ultra)mafic environments. More evolved volcanic-hydrothermal systems may also provide all the prerequisites necessary for abiogenic hydrocarbon production, such as availability of inorganic CO2, hydrogen and heat. We have investigated the chemical and isotopic composition of n-alkanes contained within subaerial hydrothermal discharges emitted from a range of hot spot, subduction and rift-related volcanoes to determine the origin of hydrocarbons in these systems. Amongst these are Nisyros (Greece), Vesuvio, Campi Flegrei, Ischia, Pantelleria and Vulcano (all Italy), Mt. Mageik and Trident (USA), Copahue (Argentina), Teide (Spain), Furnas and Fogo (Portugal). The carbon isotopic composition of methane emitted from these sites varies from -65 to -8‰ , whereas δ13C of ethane and propane exhibit a much narrower variation from -17‰ to -31‰. Methane that occurs most enriched in 13C is also characterized by relatively positive δD values ranging up to -80‰. Carbon isotope reversals between methane and ethane are only observed for locations exhibiting δ13C-CH4 values > -20‰, such as Teide, Pantelleria, Trident and Furnas. At Furnas, δ13C-CH4 varies by 50‰ within a relatively short distance of <50m between two vents, whereas δ13C-C2H6 varies by less than 2‰ only. For some of the investigated locations apparent carbon isotopic temperatures between methane and CO2 are in agreement with those derived from gas concentration geothermometers. At these locations methane, however seems to be in disequilibrium with ethane and propane. These findings imply that methane on the one hand and the C2+ hydrocarbons on the other hand often might derive from distinct sources.

El ogro Filantrópico

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Paz Octavio

1998-06-01

Full Text Available Los liberales creían que, gracias al desarrollo de la libre empresa, florecería la sociedad civil y, simultáneamente, la función del Estado se reduciría a la de simple supervisor de la evolución espontánea de la humanidad. Los marxistas, con mayor optimismo, pensaban que el siglo de la aparición del socialismo sería también el de la desaparición del Estado. Esperanzas y profecías evaporadas: el Estado del siglo XX se ha revelado como una fuerza más poderosa que la de los antiguos imperios y como un amo más terrible que los viejos tiranos y déspotas.

Analysis of Economic and Social Effects of Pueblo Viejo Mining Project

DEFF Research Database (Denmark)

Parra, Cristian; Pacheco Cueva, Vladimir

some key recommendations to effectively transform its effects into social capital and an improved level of human development. Current market conditions and new mining projects are providing extraordinary, positive and long term possibilities for improving the social and economic wellbeing in host......The research was conducted during the last quarter of 2010 and the first semester of 2011. It included planning the field work, conducting interviews, collecting data, reviewing secondary sources of information, carrying out analysis, internal and external session discussions and writing up...... the final report. This document contributes to the ongoing understanding of the potential impacts and effects of the Pueblo Viejo mining project on the human development and general progress of the people of Dominican Republic. We explain the most significant and potential effects of the project and provide...

Embarazo ectópico abdominal

OpenAIRE

Karen Luz Torres Rojas; Miguel Blanco Paz; Gerardo Celorrio Montiel

2015-01-01

La incidencia de embarazo ectópico ha aumentado en los últimos años hasta 1:43 recién nacidos. La variedad abdominal es una de las menos frecuentes, su incidencia es de 1:10mil  nacidos vivos. El 1% de los embarazos ectópicos son abdominales y la implantación en el epiplón es una rara entidad. Pueden clasificarse como primarios o secundarios en función de que se originen o no en la cavidad peritoneal. Se presenta un caso de embarazo abdominal primario, localizado en cara posterior del útero y...

Eficacia del diclofenaco tópico vs. nepafenaco tópico en la reducción del dolor durante la fotocoagulación panretiniana

OpenAIRE

Hernández-Camarena, Julio C.; Valdez-García, Jorge E.; Rodríguez-García, Alejandro

2016-01-01

Propósito: Comparar la eficacia del diclofenaco tópico 0.1% vs. nepafenaco tópico en reducir el dolor asociado a la fotocoagulación panretiniana con láser argón. Material y métodos: Ensayo clínico aleatorizado doble enmascarado, 132 pacientes (183 ojos) con diagnóstico de retinopatía diabética proliferativa tratados con fotocoagulación panretiniana. Aleatorización en 2 grupos: diclofenaco y nepafenaco tópicos. Se aplicaron 2 dosis de los analgésicos tópicos previas a la fotocoagulación pan...

Jóvenes y viejos: ¿el cuerpo como locus de identidad?

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Liuba Kogan

2011-03-01

Full Text Available En el texto se discute acerca de la importancia del cuerpo como locus de la identidad de dos cohortes de edad diferentes: la de los jóvenes y los viejos. Para ello se toma en cuenta las ideas de Baudrillard sobre la falta de profundidad del cuerpo y su conversión en simulacro; contrastándose con los resultados de una investigación empírica cualitativa llevada a cabo en la ciudad Lima en el año 2006 a partir de entrevistas en profundidad con 36 hombres y mujeres de diversas clases sociales y edades. Se encuentra básicamente, que la vivencia de cuerpo como locus de la identidad varía según grupos de edad y según género; por lo que se relativizan los postulados de Baudrillard.

Unusual Vermamoeba Vermiformis Strain Isolated from Snow in Mount Teide, Tenerife, Canary Islands, Spain

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Maria Reyes-Batlle

2015-10-01

Full Text Available Background: Free-living amoebae (FLA are protozoa that are widely distributed in the environment mainly in water and soil related habitats. Thermophilic amoebae are among the most common FLA in water bodies, being Vermamoeba vermiformis one of the most common species reported worldwide from these sources. Interestingly, V. vermiformis has often been reported to survive at high temperatures and osmotic pressure worldwide.Materials and Methods: In this study, snow samples were collected from Mount Teide, Tenerife, Canary Islands during the winter season of 2014. The samples were culture on non nutrient agar plates and checked daily for the presence of FLA. After a week, V. vermiformis amoebae were observed in the plates incubated at room temperature and 37ºC.Results: Molecular characterization was carried out by amplifying the 18S rDNA gene and DNA sequencing, confirmed that the isolated strain belonged to Vermamoeba vermiformis species.Conclusion: To the best of our knowledge, this is the first report of Vermamoeba vermiformis isolation from such an inusual habitat (low temperatures and high altitude and the first report of these species in the Canary islands.

PRESENCIA DEL VIRUS DE INFLUENZA AVIAR EN AVES SILVESTRES DE LOS HUMEDALES DE PUERTO VIEJO, LIMA

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Segovia H., Karen; Icochea D., Eliana; González V., Rosa; Ghersi, Bruno; González Z., Armando

2013-01-01

El objetivo del estudio fue determinar la presencia del virus de influenza aviar (IA) en aves silvestres presentes en los Humedales de Puerto Viejo, en el departamento de Lima. Novecientas muestras de heces frescas de 18 especies de aves silvestres fueron colectadas desde abril de 2008 hasta febrero de 2009. Dichas muestras se analizaron mediante aislamiento viral en huevos embrionados de pollo SPF. Se logró aislar siete cepas de virus de IA de baja patogenicidad del subtipo H12N5 (seis cepas...

La incorporación y representaciones espaciales del Nuevo Mundo en el Viejo Mundo

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Alejandra Toscana Aparicio

2012-02-01

Full Text Available En este trabajo se propone una aproximación para el estudio del paisaje, considerándolo como un conjunto de elementos tanto físico-naturales como sociales, configurado a través de procesos histórico-culturales, susceptible de ser representado simbólicamente. Se analizan tres diversas maneras de relación espacio físicocultura, que oscilan entre el “compromiso” y el “distanciamiento”, y que dan lugar a variadas formas de representación del espacio, las cuales ordenan la experiencia espacial y producen identidades. El descubrimiento del Nuevo Mundo y sus representaciones en el Viejo Mundo se utilizan como ejemplo.

Magma mixing in the 1100 AD Montaña Reventada composite lava flow, Tenerife, Canary Islands: interaction between rift zone and central volcano plumbing systems

Science.gov (United States)

Wiesmaier, S.; Deegan, F. M.; Troll, V. R.; Carracedo, J. C.; Chadwick, J. P.; Chew, D. M.

2011-09-01

Zoned eruption deposits commonly show a lower felsic and an upper mafic member, thought to reflect eruption from large, stratified magma chambers. In contrast, the Montaña Reventada composite flow (Tenerife) consists of a lower basanite and a much thicker upper phonolite. A sharp interface separates basanite and phonolite, and chilled margins at this contact indicate the basanite was still hot upon emplacement of the phonolite, i.e. the two magmas erupted in quick succession. Four types of mafic to intermediate inclusions are found in the phonolite. Inclusion textures comprise foamy quenched ones, others with chilled margins and yet others that are physically mingled, reflecting progressive mixing with a decreasing temperature contrast between the end-members. Analysis of basanite, phonolite and inclusions for majors, traces and Sr, Nd and Pb isotopes show the inclusions to be derived from binary mixing of basanite and phonolite end-members in ratios of 2:1 to 4:1. Although, basanite and phonolite magmas were in direct contact, contrasting 206Pb/204Pb ratios show that they are genetically distinct (19.7193(21)-19.7418(31) vs. 19.7671(18)-19.7807(23), respectively). We argue that the Montaña Reventada basanite and phonolite first met just prior to eruption and had limited interaction time only. Montaña Reventada erupted from the transition zone between two plumbing systems, the phonolitic Teide-Pico Viejo complex and the basanitic Northwest rift zone. A rift zone basanite dyke most likely intersected the previously emplaced phonolite magma chamber. This led to eruption of geochemically and texturally unaffected basanite, with the inclusion-rich phonolite subsequently following into the established conduit.

"Estoy viejo" [I'm old]: internalized ageism as self-referential, negative, ageist speech in the Republic of Panama.

Science.gov (United States)

Campos, Irma D; Stripling, Ashley M; Heesacker, Martin

2012-12-01

Ageism is a form of discrimination that anyone may experience at some point in life (Palmore 2004). Yet ageism is rarely the focus of behavioral research (Nelson 2005). Age can be understood as a social construct that reflects social norms (Lemus and Exposito 2005). Based on our review of the published literature, there were two studies on perceptions of aging among Latina/os in the United States (Beyene et al. 2002; Sarkisian et al. 2006). These studies investigated perceptions and expectations of aging among older Latina/o adults rather than direct experiences of ageism. It is important to note that Latina/os are not a homogenous group and that there are within-group differences. For this reason, this study explored internalized, negative ageism specifically in the Republic of Panama. Although Panama has unique characteristics, it also reflects Central American culture and therefore should provide initial insights regarding Central American self-referential, negative, ageist talk, which we labeled "Estoy viejo." Flanagan's Critical Incident Technique was used to access and understand participants' (ages 18-65) negative ageist talk (n=159). Participants who reported engaging in "Estoy viejo." (46.3% of those sampled) were significantly younger than participants who did not (pexplanation is that younger participants may have been more influenced by North American culture and its strongly negative ageist stereotypes than older participants, who may have identified primarily with Central American culture.

Los Rumiantes (Artiodactyla, Mammalia del Mioceno inferior de La Encinilla (Colmenar Viejo, Madrid

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Morales, J.

2006-12-01

Full Text Available This article is a preliminary study of the fossil ruminants found in the Early Miocene site of La Encinilla (Colmenar Viejo, Madrid. The morphological description of dentition and postcranial bones, along with the metrical and comparative study with material from localities of similar age in France and Spain has allowed us to confirm the presence of two Pecoran ruminants in La Encinilla: Andegameryx sp. and a larger species related to Teruelia Moyá-Solá, 1987. Although the identification in one of the cases should be confirmed with more material, the record in the Madrid Bassin would represent new information regarding the known biogeographical distribution of both taxa. The systematic position of Andegameryx and Teruelia is still under discussion, but both forms are clearly distinct from the Cervoidea ruminants found in Europe and the Iberian Peninsula at the same age, such as Amphitragulus, Oriomeryx, Bedenomeryx or Dremotherium.Este trabajo constituye un estudio preliminar de los restos de rumiantes fósiles hallados en el yacimiento del Mioceno inferior de La Encinilla (Colmenar Viejo, Madrid. La descripción morfológica de la dentición y del esqueleto postcraneal, así como el estudio métrico y comparativo con material procedente de localidades francesas y españolas de edad similar ha permitido constatar hasta el momento la presencia de dos formas de rumiantes Pecora en La Encinilla: Andegameryx sp. y un rumiante de mayor talla relacionado con Teruelia Moyá-Solá, 1987. Aunque la identificación en uno de los casos necesitaría confirmarse con más material, la presencia de estas dos formas en la Cuenca de Madrid ampliaría la distribución biogeográfica conocida para ambos taxones. La posición sistemática de Andegameryx y Teruelia permanece abierta a discusión, pero ambos géneros se diferencian de los Cervoidea del Mioceno inferior encontrados en Europa y la Península Ibérica, tales como Amphitragulus, Oriomeryx, Bedenomeryx

Noticias de Francisco de Herrera el Viejo en Madrid y del retablo mayor del Colegio de San Basilio, de Sevilla

Directory of Open Access Journals (Sweden)

Cornejo, Francisco J.

2006-12-01

Full Text Available Documents are presented here attesting to the presence of the painter Francisco de Herrera el Viejo in Madrid between 1647 and 1648. Likewise, important new information concerning the altarpiece of San Basilio in Seville is brought to light: the measurements of the architectural structure, the delay of almost ten years in its installation and payment to the artist; and, above all, the three paintings now located – a Christ Child from the door of the ciborium, and the portraits of Saint Basil the Great and Saint Eumelia, parents of Saint Basil – still attached to a fragment of the original alterpiece.

En este artículo se dan a conocer documentos que certifican la presencia en Madrid del pintor Francisco de Herrera el Viejo en 1647 y 1648. Además, se aportan importantes novedades acerca del retablo de San Basilio, de Sevilla: las medidas de su arquitectura; el retraso en casi diez años de su instalación y pago al pintor; y, sobre todo, las tres pinturas localizadas - un Niño Jesús, de la puerta del sagrario y los retratos de San Basilio el Mayor y de Santa Eumelia, padres de San Basilio - que continúan insertas en un fragmento del retablo original.

El conjunto termal de la llamada Villa del Camino Viejo de las Sepulturas (Balazote, Albacete

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Virginia García Entero

1997-01-01

Full Text Available Entre las construcciones más emblemáticas y fáciles de identificar en los asentamientos romanos rurales, genéricamente conocidos bajo el apelativo de villa, se encuentran las dependencias termales, índice no sólo del grado de comodidad que alcanzaron estos establecimientos, sino también, en función de las dimensiones, esquema de uso y programa decorativo empleado, de la riqueza de sus propietarios. El conjunto termal de la villa albacetense del Camino Viejo de Las Sepulturas (Balazote, hasta ahora conocido tan sólo muy parcialmente, formó parte, por las razones expuestas, de un grupo de edificios balnearios rústicos asociados a grandes latifundios bajo imperiales y verdaderos conjuntos palatinos. Las fotografías inéditas de su excavación y el estudio exhaustivo del sistema constructivo nos ha permitido interpretar esta importante instalación  termal y establecer una hipótesis de reconstrucción de su esquema de funcionamiento.Among the more emblematic and easy to identify constructions in Román rural sites, generically known as villa, are the thermal rooms. These rooms indícate not only the level of comfort reached by the Román villae but also, according to the dimensions, function plan and decorative programe, the owner's wealth. The thermal building of the villa of Camino Viejo de las Sepulturas (Balazote, Albacete up to date known only quite partíally, was, considering the above mentioned characteristics, a part of a group of rustic bath suites associated with large states dating from the Late Román Empire and with real palatine complexes. The unpublished photographs of its excavation and the comprenhensive study of the system allowed us to these rievant thermal as well as to establish a hypothesis of its function plan.

Nuclear order in silver at pico-Kelvin temperature

DEFF Research Database (Denmark)

Siemensmeyer, K.; Clausen, K.N.; Lefmann, K.

1997-01-01

Nuclear order in silver is observed by neutron diffraction at pico-Kelvin temperatures. The structure is a type-I antiferromagnet with critical field of 100 mu T. The entropy-field phase diagram was determined using the spin-dependent absorption.......Nuclear order in silver is observed by neutron diffraction at pico-Kelvin temperatures. The structure is a type-I antiferromagnet with critical field of 100 mu T. The entropy-field phase diagram was determined using the spin-dependent absorption....

Mysteries of attraction: Giovanni Pico della Mirandola, astrology and desire.

Science.gov (United States)

Rutkin, H Darrel

2010-06-01

Although in his later years Giovanni Pico della Mirandola (1463-1494) vehemently rejected astrology, he earlier used it in a variety of ways, but primarily to provide further evidence for positions to which he had arrived by other means. One such early use appears in his commentary on his friend Girolamo Benivieni's love poetry, the Canzone d'amore, of 1486-1487. In the passages discussed here, Pico presents an intensive Platonic natural philosophical analysis based on a deep astrologically informed understanding of human nature as he attempts to explain a perennial question, namely, why one person is attracted to a certain person (or people), and another to others. I will place this discussion of the mysteries of attraction and desire in historical perspective by tracing Pico's changing relationship to astrology during the course of his short but passionate life, and in historiographic perspective by revising Frances Yates's still influential views concerning Pico's contribution to Renaissance thought and his relationship with Marsilio Ficino.

Acondicionamiento de la plaza del viejo mercado en Rouen – Francia

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Arretche, L.

1980-06-01

Full Text Available The aim sought in conditioning the Old Market square of Rouen has been to integrate three elements of very different functions in a harmonious unit. These are: — the church — the covered market, and — the Joan of Arc national monument. The various frameworks are based on the traditional naval construction and are made up of tuned surfaces: hyperbolic paraboloids made in wood. The thirteen XVI century stained glass windows miraculously saved from the destruction of Saint Vincent's Church are an outstanding feature.

Con el acondicionamiento de la plaza del Viejo Mercado de Rouen se ha pretendido integrar en un conjunto armonioso tres elementos de tan distintas funciones como son: — la iglesia, — el mercado cubierto, y — el monumento nacional a Juana de Arco. Los diversos entramados se basan en la construcción naval tradicional y están constituidos por superficies regladas: paraboloides hiperbólicos hechos de madera. Destacan en el conjunto las trece vidrieras del siglo XVI, salvadas milagrosamente de la destrucción de la iglesia de San Vicente.

Pico hydro turbines for electricity in rural areas

OpenAIRE

Descotte, Gérard

2016-01-01

This article discusses the feedback and lessons learned, particularly from a survey carried out following the deployment program of a pico hydro power solution in a very isolated rural area in north Laos. This project is part of the strategic development for the rural electrification of Laos, in which pico hydro power facilities constitute the main avenue of progress for the electrification of isolated villages.

PicoGreen dye as an active medium for plastic lasers

Science.gov (United States)

Pradeep, C.; Vallabhan, C. P. G.; Radhakrishnan, P.; Nampoori, V. P. N.

2015-08-01

Deoxyribonucleic acid lipid complex thin films are used as a host material for laser dyes. We tested PicoGreen dye, which is commonly used for the quantification of single and double stranded DNA, for its applicability as lasing medium. PicoGreen dye exhibits enhanced fluorescence on intercalation with DNA. This enormous fluorescence emission is amplified in a planar microcavity to achieve yellow lasing. Here the role of DNA is not only a host medium, but also as a fluorescence dequencher. With the obtained results we have ample reasons to propose PicoGreen dye as a lasing medium, which can lead to the development of DNA based bio-lasers.

The impact of PICO as a search strategy tool on literature search quality

DEFF Research Database (Denmark)

Eriksen, Mette Brandt; Frandsen, Tove Faber

2018-01-01

Objective: This review aimed to determine, if the use of the PICO model (Patient Intervention Comparison Outcome) as a search strategy tool affects the quality of the literature search. Methods: A comprehensive literature search was conducted in: PubMed, Embase, CINAHL, PsycInfo, Cochrane Library...... and three studies were included, data was extracted, risk of bias was assessed and a qualitative analysis was conducted. The included studies compared PICO to PIC or link to related articles in PubMed; PICOS and SPIDER. One study compared PICO to unguided searching. Due to differences in intervention...

Acidente de trabalho típico e bipoder

OpenAIRE

Luz,Leonardo Del Puppo; Andrade,Ângela Nobre de

2012-01-01

Contemporaneamente, os acidentes de trabalho típico ainda vêm se mantendo como uma temática extremamente relevante à malha social. A Previdência (INSS), em 2007, registrou 653.090 acidentes de trabalho. Diante desse quadro estatístico, diversos órgãos públicos têm se empenhado no enfrentamento das ocorrências caracterizadas como acidentes de trabalho típico (ATs). Esta pesquisa originou-se de parte da dissertação que almejou colocar em análise práticas que permeiam as investigações de determi...

Pico photovoltaic: a macro impact in Africa?

International Nuclear Information System (INIS)

Vine, Elise; Dumas, Benoit

2016-01-01

As it seems there is a market for small size solar kits (or 'pico-photovoltaic' devices) in Sub-Saharan Africa (between 2012 and 2014, the number of people having a better access to energy thanks to these devices increased from 4 millions to 35 millions), this paper aims at assessing the economic viability of these devices, at seeing how to give access to these products for rural and disadvantaged populations. It highlights innovations implemented by actors of this sector in terms of business models, technologies, distribution channels, or partnerships. Thus, the authors propose an overview of the situation of solar energy in Africa, outline that pico photovoltaic could help to overcome a poor electrification. They discuss the specificities of these devices and present some examples of solar lamps. They analyse the economic, medical, environmental, and educative impacts of these devices as well as their impact on well-being and safety. They briefly indicate the main actors of off-grid solar energy and micro-grid solar energy. They discuss the issue of financing, that of distribution, credit possibilities (pay-as-you-go, micro-credit), and finally propose an overview of the African market, with notably the example of solar pico-lamps

Answering PICO Clinical Questions: a Semantic Graph-Based Approach

OpenAIRE

Znaidi , Eya; Tamine , Lynda; Latiri , Chiraz

2015-01-01

International audience; In this paper, we tackle the issue related to the retrieval of the best evidence that fits with a PICO (Population, Intervention, Comparison and Outcome) question. We propose a new document ranking algorithm that relies on semantic based query expansion bounded by the local search context to better discard irrelevant documents. Experiments using a standard dataset including 423 PICO questions and more than 1,2 million of documents, show that our aproach is promising.

Experience of pico/micro hydro based power generation

Energy Technology Data Exchange (ETDEWEB)

Murthy, S.S. [Indian Inst. of Technology, Delhi, New Delhi (India). Dept. of Electrical Engineering

2010-07-01

Although India has approximately 150,000 megawatts of hydro potential, only a small portion is tapped. There is also significant untapped hydro potential in many developing countries such as Nepal, Bhutan, Vietnam, Indonesia and regions in South America and Africa. Small-scale hydroelectric power systems with capacities of up to a few megawatts are eco-friendly and sustainable. They can be classified based on unit sizes as pico (u pto 10 kilowatts), micro (10-100 kilowatts) and mini (100 kilowatts to a few megawatts) hydro systems. Mini hydro systems are always grid connected while micro can be either grid connected or off grid. Pico is always off grid. In India, there are thousands of favorable sites in this range that should be tapped for distributed power generation to electrify local communities. This need is reflected by the global emphasis on distributed power generation as well as the Government of India's policy to promote this type of power generation. A working stand alone pico-hydro power generating system has been successfully installed in 5 sites in Karnataka. The purpose of the project was to demonstrate the technical, managerial and economic feasibility of setting up small hydro projects in remote hilly areas of Karnataka, India and its positive environmental impact. The presentation discussed the site selection criteria; installed sites of pico hydro; system description; parts of the system; the electric load controller; types of electronic load controllers; and a description of the unit and control scheme. tabs., figs.

Os oito odiados: o cinema épico de Quentin Tarantino

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Rosana Cristina Zanelatto Santos

2017-12-01

Full Text Available Propomos, neste artigo, uma leitura da película Os oito odiados (2015, de Quentin Tarantino, naquilo em que ela pode ser aproximada do teatro épico de Bertolt Brecht, utilizando, para qualificá-la, a rubrica cinema épico. Os objetivos deste trabalho são refletir sobre: a dinâmica dos gêneros, a importância da funcionalidade e do efeito para os estudos sobre os gêneros e o papel didático (como postulado por Brecht para seu teatro épico do cinema de Tarantino. Para tanto, analisamos os modos pelos quais Os oito odiados desenvolve o papel didático, encenando situações-limites do ser humano e promovendo reflexões em torno de possíveis questões que impelem o ser humano rumo à violência. Para a leitura dessa película, valemo-nos das perspectivas teóricas de Wolfgang Kayser sobre o gênero, de Noé Jitrik sobre o efeito, de Bertolt Brecht e de Anatol Rosenfeld sobre o teatro épico e de Ariano Suassuna sobre as relações possíveis entre teatro e cinema.

CONHECIMENTO DE IDOSAS SOBRE O USO DE PSICOTRÓPICOS

OpenAIRE

Fabrícia Araújo Prudêncio; Lidya Tolstenko Nogueira

2013-01-01

Del proceso de envejecimiento pueden emergí enfermedades y necesidad de medicamentos psicotrópicos. Esta investigación exploratoria y descriptiva, con enfoque cualitativo, tuvo como objetivo describir el conocimiento de ancianos acerca del uso de medicamentos psicotrópicos. Se entrevistaron a 18 pacientes durante de julio a agosto de 2009, registrados en la Estrategia de Salud Familiar que utilizaban benzodiazepina y/o antidepresivos. Los datos fueron organizados basados en la técnica de anál...

Situação do registro de medicamentos fitoterápicos no Brasil

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Ana C. B. Carvalho

Full Text Available Fitoterápico é uma classe de medicamento largamente utilizada no país e constitui um mercado em potencial expansão. Este artigo busca traçar um panorama sobre os medicamentos fitoterápicos registrados no país e as espécies vegetais que lhe deram origem, enfocando o papel regulador da Anvisa. Realizou-se uma pesquisa nas seguintes bases de dados: Visalegis e site da Anvisa para verificar os medicamentos fitoterápicos registrados na Anvisa, obtendo-se os seguintes dados: há 432 fitoterápicos simples registrados e 80 compostos, as espécies vegetais com maior número de derivados registrados são o Ginkgo (Ginkgo biloba e a Castanha da Índia (Aesculus hippocastanum, com 33 e 29 registros, respectivamente. O artigo traz ainda uma tabela com as espécies vegetais que possuem derivados registrados como fitoterápicos simples, sua classificação terapêutica, lista as espécies registradas em associação, as principais formas farmacêuticas registradas e os percentuais de registro e empresas por região do país, fornecendo assim um panorama da atuação da Anvisano setor de fitoterápicos.

Diabetes mellitus e antipsicóticos atípicos

OpenAIRE

Sena, Eduardo Pondé de; Sampaio, Aline Santos; Quarantini, Lucas de Castro; Oliveira, Irismar Reis de

2003-01-01

p.:253-257 Pacientes esquizofrênicos têm maior risco para desenvolvimento de transtorno hiperglicêmico e o uso de antipsicóticos parece ampliar o risco de desenvolvimento de diabetes mellitus. O presente trabalho é uma revisão da literatura acerca da relação entre antipsicóticos atípicos e risco de desenvolvimento de diabetes mellitus. A pesquisa bibliográfica foi realizada por meio dos bancos de dados Medline e Webofscience enfocando os seguintes tópicos: "Hyperglycemia", "Diabetes Mellit...

Effectiveness of Sodium Picosulfate/Magnesium Citrate (PICO) for Colonoscopy Preparation

Science.gov (United States)

Suh, Wu Seok; Jeong, Jin Sik; Kim, Dong Sik; Kim, Sang Woo; Kwak, Dong Min; Hwang, Jong Seong; Kim, Hyun Jin; Park, Man Woo; Shim, Min Chul; Koo, Ja-Il; Kim, Jae Hwang; Shon, Dae Ho

2014-01-01

Purpose Bowel preparation with sodium phosphate was recently prohibited by the U.S. Food and Drug Administration. Polyethylene glycol (PEG) is safe and effective; however, it is difficult to drink. To identify an easy bowel preparation method for colonoscopy, we evaluated three different bowel preparation regimens regarding their efficacy and patient satisfaction. Methods In this randomized, comparative study, 892 patients who visited a secondary referral hospital for a colonoscopy between November 2012 and February 2013 were enrolled. Three regimens were evaluated: three packets of sodium picosulfate/magnesium citrate (PICO, group A), two packets of PICO with 1 L of PEG (PICO + PEG 1 L, group B), and two packets of PICO with 2 L of PEG (PICO + PEG 2 L, group C). A questionnaire survey regarding the patients' preference for the bowel preparation regimen and satisfaction was conducted before the colonoscopies. The quality of bowel cleansing was scored by the colonoscopists who used the Aronchick scoring scale and the Ottawa scale. Results The patients' satisfaction rate regarding the regimens were 72% in group A, 64% in group B, and 45.9% in group C. Nausea and abdominal bloating caused by the regimens were more frequent in group C than in group A or group B (P < 0.01). Group C showed the lowest preference rate compared to the other groups (P < 0.01). Group C showed better right colon cleansing efficacy than group A or group B. Conclusion Group A exhibited a better result than group B or group C in patient satisfaction and preference. In the cleansing quality, no difference was noted between groups A and C. PMID:25360429

Soil CO2 efflux measurement network by means of closed static chambers to monitor volcanic activity at Tenerife, Canary Islands

Science.gov (United States)

Amonte, Cecilia; García-Merino, Marta; Asensio-Ramos, María; Melián, Gladys; García-Hernández, Rubén; Pérez, Aaron; Hernández, Pedro A.; Pérez, Nemesio M.

2017-04-01

Tenerife (2304 km2) is the largest of the Canary Islands and has developed a central volcanic complex (Cañadas edifice), that started to grow about 3.5 My ago. Coeval with the construction of the Cañadas edifice, shield basaltic volcanism continued until the present along three rift zones oriented NW-SE, NE-SW and NS (hereinafter referred as NW, NE and NS respectively). Main volcanic historical activity has occurred along de NW and NE rift-zones, although summit cone of Teide volcano, in central volcanic complex, is the only area of the island where surface geothermal manifestations are visible. Uprising of deep-seated gases occurs along the aforementioned volcanic structures causing diffuse emissions at the surface environment of the rift-zones. In the last 20 years, there has been considerable interest in the study of diffuse degassing as a powerful tool in volcano monitoring programs. Diffuse degassing studies are even more important volcanic surveillance tool at those volcanic areas where visible manifestations of volcanic gases are absent. Historically, soil gas and diffuse degassing surveys in volcanic environments have focused mainly on CO2 because it is, after water vapor, the most abundant gas dissolved in magma. One of the most popular methods used to determine CO2 fluxes in soil sciences is based on the absorption of CO2 through an alkaline medium, in its solid or liquid form, followed by gravimetric, conductivity, or titration analyses. In the summer of 2016, a network of 31 closed static chambers was installed, covering the three main structural zones of Tenerife (NE, NW and NS) as well as Cañadas Caldera with volcanic surveillance porpoises. 50 cc of 0.1N KOH solution is placed inside the chamber to absorb the CO2 released from the soil. The solution is replaced weekly and the trapped CO2 is then analyzed at the laboratory by titration. The are expressed as weekly integrated CO2 efflux values. The CO2 efflux values ranged from 3.2 to 12.9 gṡm-2�

Riesgos antrópicos generados por la actividad minera

OpenAIRE

Ana Violeta Argüello Mejía; Enriqueta Cantos Aguirre; Jorge Vitery Moya

2013-01-01

Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y Calacalí, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican qu...

Energy Efficient Pico Cell Range Expansion and Density Joint Optimization for Heterogeneous Networks with eICIC

Directory of Open Access Journals (Sweden)

Yanzan Sun

2018-03-01

Full Text Available Heterogeneous networks, constituted by conventional macro cells and overlaying pico cells, have been deemed a promising paradigm to support the deluge of data traffic with higher spectral efficiency and Energy Efficiency (EE. In order to deploy pico cells in reality, the density of Pico Base Stations (PBSs and the pico Cell Range Expansion (CRE are two important factors for the network spectral efficiency as well as EE improvement. However, associated with the range and density evolution, the inter-tier interference within the heterogeneous architecture will be challenging, and the time domain Enhanced Inter-cell Interference Coordination (eICIC technique becomes necessary. Aiming to improve the network EE, the above factors are jointly considered in this paper. More specifically, we first derive the closed-form expression of the network EE as a function of the density of PBSs and pico CRE bias based on stochastic geometry theory, followed by a linear search algorithm to optimize the pico CRE bias and PBS density, respectively. Moreover, in order to realize the pico CRE bias and PBS density joint optimization, a heuristic algorithm is proposed to achieve the network EE maximization. Numerical simulations show that our proposed pico CRE bias and PBS density joint optimization algorithm can improve the network EE significantly with low computational complexity.

Debris Avalanches and Debris Flows Transformed from Collapses in the Trans-Mexican Volcanic Belt, México.

Science.gov (United States)

Capra, L.; Macias, J.; Scott, K.; Abrams, M.; Garduño, V.

2001-12-01

Volcanoes of the Trans-Mexican Volcanic Belt (TMVB) have yielded numerous sector and flank collapses during Pleistocene and Holocene time. Sector collapses associated with magmatic activity have yielded debris avalanches with generally limited runout extent (e.g. Popocatépetl, Jocotitlán, and Colima volcanoes). In contrast, flank collapses (smaller failures not involving the volcano summit), both associated and unassociated with magmatic activity and correlated with intense hydrothermal alteration in ice-capped volcanoes, commonly have yielded highly mobile cohesive debris flows (e.g. Pico de Orizaba and Nevado de Toluca volcanoes). Collapse orientation in the TMVB is preferentially to the south and north-east, probably reflecting the tectonic regime of active E-W and NNW faults. The different mobilities of the flows transformed from collapses have important implications for hazard assessment. Both sector and flank collapse can yield highly mobile debris flows, but this transformation is more common in the case of the smaller failures. High mobility is related to factors such as water and clay content of the failed material, the paleotopography, and the extent of entrainment of sediment during flow (bulking). Both debris-avalanches and debris-flows are volcanic hazards that occur from both active volcanoes, as well as those that are inactive or dormant volcanoes, and may by triggered by earthquakes, precipitation, or simple gravity. There will be no precursory warning in such non-volcanic cases.

Pico Lantern: a pick-up projector for augmented reality in laparoscopic surgery.

Science.gov (United States)

Edgcumbe, Philip; Pratt, Philip; Yang, Guang-Zhong; Nguan, Chris; Rohling, Rob

2014-01-01

The Pico Lantern is proposed as a new tool for guidance in laparoscopic surgery. Its miniaturized design allows it to be picked up by a laparoscopic tool during surgery and tracked directly by the endoscope. By using laser projection, different patterns and annotations can be projected onto the tissue surface. The first explored application is surface reconstruction. The absolute error for surface reconstruction using stereo endoscopy and untracked Pico Lantern for a plane, cylinder and ex vivo kidney is 2.0 mm, 3.0 mm and 5.6 mm respectively. The absolute error using a mono endoscope and a tracked Pico Lantern for the same plane, cylinder and kidney is 0.8mm, 0.3mm and 1.5mm respectively. The results show the benefit of the wider baseline produced by tracking the Pico Lantern. Pulsatile motion of a human carotid artery is also detected in vivo. Future work will be done on the integration into standard and robot-assisted laparoscopic surgery.

Antropo-Semiótica del cambio ritual: de los viejos a los nuevos ritos

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José Enrique Finol

2014-07-01

Full Text Available Algunas de las preguntas claves que debemos hacernos cuando comparamos viejos ritos –religiosos, cósmicos, cíclicos– con los nuevos ritos propios de las sociedades modernas, donde han irrumpido con fuerza los medios de difusión masiva, son cuáles rasgos constituyen sus diferencias, en qué niveles y circunstancias dichas diferencias se realizan, por qué unos ritos cambian radicalmente y otros no, de dónde proceden esos cambios y qué los facilita; lo que conduce, a su vez, a preguntarse por su orientación y dirección semiótica. Nuestro análisis comparativo de antiguos y modernos ritos nos muestra diferencias en cuatro órdenes distintos: las dimensiones de las formas, la rigidez de las normas, los límites del escenario y la esfera de la comunicación. Ese análisis nos permitirá clasificar los cambios de ritos en intra-rituales, inter-rituales y trans-rituales.

Magma Diversity in the Trans-Mexican Volcanic Belt: the role of Mantle Heterogeneities, Slab-derived Fluxes and Crustal Contamination.

Science.gov (United States)

Schaaf, P.; Valdez, G.; Siebe, C.; Carrasco, G.

2005-12-01

The Plio-Quaternary Trans-Mexican Volcanic Belt (TMVB) is related to subduction of the Cocos and Rivera plates underneath the North American plate. Non-parallelism of the magmatic arc with respect to the trench can be explained by oblique subduction and changes of dip angle. In this contribution we compare geochemical and Sr-Nd-Pb isotope data of five TMVB stratovolcanoes (from east to west: Colima Volcano, Nevado de Toluca, Popocatepetl, La Malinche, and Pico de Orizaba) and associated cinder cones. Volcanic products range in stratovolcanoes from andesites (e.g. Colima, Popocatepetl) to rhyolites (e.g. Pico de Orizaba), and from basalts to andesites in the monogenetic cones. Concentrations of incompatible elements correlate positively with Sr-Nd-Pb isotope ratios from east to west along the arc. 87Sr/86Sr, eNd, and 206Pb/204Pb range from 0.7034-0.7050, +6.9 to minus 1.8, and 18.57-18.78, respectively, displaying considerable differences. In the central TMVB, REE patterns of closely spaced high-Mg basaltic andesites differ substantially. This cannot be explained by fractional crystallization processes or differential partial melting of a homogeneous mantle source. Instead, it points towards small-scale mantle heterogeneities. LILE (e.g. Cs, Rb, Ba, Pb) and HFSE (e.g. Ta, Nb, Zr) display variations of orders in magnitude at different segments along the arc. These variations might correlate with amounts of slab-derived aqueous fluids and intensity of metasomatic reactions between the subducting lithosphere and the overlying mantle wedge. Isotopic ratios of mid-lower crustal xenoliths found in nearly all stratovolcano products reflect the nature of the underlying crust beneath the TMVB. Tertiary-Cretaceous plagiogranites (Colima), Cretaceous limestones (Popocatepetl), and Grenvillian quartzites (Pico de Orizaba)and their increasing radiogenic isotope ratios match well with the observed isotopic signatures of the stratovolcanoes. Moreover, elevated CO2 amounts in

PICO DELLA MIRANDOLA Y SAVONAROLA

Directory of Open Access Journals (Sweden)

Jorge Velázquez Delgado

2013-09-01

Full Text Available En este artículo se aborda la relaciónentre Gerolamo Savonarola y GiovanniPico de la Mirandola, partiendo de labase de la amistad que sostuvieronambos y problematizando la dificultadque se presenta ante dospersonalidades aparentementeirreductibles. En tanto que símbolosemblemáticos del Renacimientoitaliano, su análisis supone un análisisde las ideas y el  ethos del período.

Volcanism on Io

Science.gov (United States)

Davies, Ashley Gerard

2014-03-01

Preface; Introduction; Part I. Io, 1610 to 1995: Galileo to Galileo: 1. Io, 1610-1979; 2. Between Voyager and Galileo: 1979-95; 3. Galileo at Io; Part II. Planetary Volcanism: Evolution and Composition: 4. Io and Earth: formation, evolution, and interior structure; 5. Magmas and volatiles; Part III. Observing and Modeling Volcanic Activity: 6. Observations: thermal remote sensing of volcanic activity; 7. Models of effusive eruption processes; 8. Thermal evolution of volcanic eruptions; Part IV. Galileo at Io: the Volcanic Bestiary: 9. The view from Galileo; 10. The lava lake at Pele; 11. Pillan and Tvashtar: lava fountains and flows; 12. Prometheus and Amirani: Effusive activity and insulated flows; 13. Loki Patera: Io's powerhouse; 14. Other volcanoes and eruptions; Part V. Volcanism on Io: The Global View: 15. Geomorphology: paterae, shields, flows and mountains; 16. Volcanic plumes; 17. Hot spots; Part VI. Io after Galileo: 18. Volcanism on Io: a post-Galileo view; 19. The future of Io observations; Appendix 1; Appendix 2; References; Index.

Generalized Phase Contrast with matched filtering using LCoS pico-projectors

OpenAIRE

Bañas, Andrew Rafael; Palima, Darwin; Glückstad, Jesper

2012-01-01

We report a beam shaping system for generating high intensity programmable opticalspots using mGPC: matched filtering combined with Generalized Phase Contrastapplying two consumer handheld pico-projectors. Such a system presents a low costalternative for optical trapping and manipulation, optical lattices and other beamshaping applications usually implemented with high-end spatial light modulators.Portable pico-projectors based on liquid crystal on silicon (LCoS) devices were usedas binary ph...

Proyecto MOP: "Concesión de defensas fluviales y carretera Ribera Norte Río Bío-Bío, sector Chiguayante-Puente Viejo"

Directory of Open Access Journals (Sweden)

Roberto Lira Olmo

2000-08-01

Full Text Available Como se indica en la Editorial, el tema central a tratar en esta edición es la perspectiva urbana en relación a los "frentes de agua" de la región y de la intercomuna Concepción-Talcahuano; y particularmente uno de los programas más emblemáticos que se están proyectando actualmente en la región: el de "Defensas Fluviales y Carretera Ribera Norte del río Bío-Bío, Chiguayante-Puente Viejo".

Acidente de trabalho típico e bipoder

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Leonardo Del Puppo Luz

2012-08-01

Full Text Available Contemporaneamente, os acidentes de trabalho típico ainda vêm se mantendo como uma temática extremamente relevante à malha social. A Previdência (INSS, em 2007, registrou 653.090 acidentes de trabalho. Diante desse quadro estatístico, diversos órgãos públicos têm se empenhado no enfrentamento das ocorrências caracterizadas como acidentes de trabalho típico (ATs. Esta pesquisa originou-se de parte da dissertação que almejou colocar em análise práticas que permeiam as investigações de determinados órgãos públicos no Estado do Espírito Santo quanto à ocorrência dos acidentes de trabalho típico, buscando expandir as problematizações acerca da binarização da culpa pelo acidente, ora atribuída ao empregador, ora ao empregado. Recorreu-se, como aporte teórico-conceitual, ao conceito-ferramenta de Biopoder desenvolvido por Michel Foucault, para lançar uma análise acerca do Biopoder e das políticas de controle dos acidentes. Conclui que se processam mecanismos de subjetivação que parecem reduzir a importância da transversalidade/atravessamentos de instituições na constituição dos acidentes de trabalho.

Analysis of Axial Turbine Pico-Hydro Electrical Power Plant in North Sulawesi Indonesia

Science.gov (United States)

Sangari, F. J.; Rompas, P. T. D.

2018-02-01

This study presents analysis of pico-hydro electrical power plant in North Sulawesi, Indonesia. The objective of this study is to get a design of axial turbine pico-hydro electrical power plant. The method used the study of literature, survey the construction site of the power plant and the characteristics of the location being a place of study, analysis of hydropower ability and analyzing costs of power plant. The result showed that the design of axial turbine pico-hydro installation is connected to a generator to produce electrical energy maximum can be used for household needs in villages. This analyze will be propose to local government of Minahasa, North Sulawesi, Indonesia.

Dark Matter Search Results from the PICO-60 C$_3$F$_8$ Bubble Chamber

Energy Technology Data Exchange (ETDEWEB)

Amole, C.; et al.

2017-02-24

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C$_3$F$_8$ located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C$_3$F$_8$ exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than 1 event per month. A blind analysis of an efficiency-corrected 1167-kg-day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the WIMP-proton spin-dependent cross section at 3.4 $\\times$ 10$^{-41}$ cm$^2$ for a 30-GeV$\\thinspace$c$^{-2}$ WIMP, more than one order of magnitude improvement from previous PICO results.

Volcanic stratigraphy: A review

Science.gov (United States)

Martí, Joan; Groppelli, Gianluca; Brum da Silveira, Antonio

2018-05-01

Volcanic stratigraphy is a fundamental component of geological mapping in volcanic areas as it yields the basic criteria and essential data for identifying the spatial and temporal relationships between volcanic products and intra/inter-eruptive processes (earth-surface, tectonic and climatic), which in turn provides greater understanding of the geological evolution of a region. Establishing precise stratigraphic relationships in volcanic successions is not only essential for understanding the past behaviour of volcanoes and for predicting how they might behave in the future, but is also critical for establishing guidelines for exploring economic and energy resources associated with volcanic systems or for reconstructing the evolution of sedimentary basins in which volcanism has played a significant role. Like classical stratigraphy, volcanic stratigraphy should also be defined using a systematic methodology that can provide an organised and comprehensive description of the temporal and spatial evolution of volcanic terrain. This review explores different methods employed in studies of volcanic stratigraphy, examines four case studies that use differing stratigraphic approaches, and recommends methods for using systematic volcanic stratigraphy based on the application of the concepts of traditional stratigraphy but adapted to the needs of volcanological environment.

The Origin of Widespread Long-lived Volcanism Across the Galapagos Volcanic Province

Science.gov (United States)

O'Connor, J. M.; Stoffers, P.; Wijbrans, J. R.; Worthington, T. J.

2005-12-01

40Ar/39Ar ages for rocks dredged (SO144 PAGANINI expedition) and drilled (DSDP) from the Galapagos Volcanic Province (Cocos, Carnegie, Coiba and Malpelo aseismic ridges and associated seamounts) show evidence of 1) increasing age with distance from the Galapagos Archipelago, 2) long-lived episodic volcanism at many locations, and 3) broad overlapping regions of coeval volcanism. The widespread nature of synchronous volcanism across the Galapagos Volcanic Province (GVP) suggests a correspondingly large Galapagos hotspot melting anomaly (O'Connor et al., 2004). Development of the GVP via Cocos and Nazca plate migration and divergence over this broad melting anomaly would explain continued multiple phases of volcanism over millions of years following the initial onset of hotspot volcanism. The question arising from these observations is whether long-lived GVP episodic volcanism is equivalent to `rejuvenescent' or a `post-erosional' phase of volcanism that occurs hundreds of thousands or million years after the main shield-building phase documented on many mid-plate seamount chains, most notably along the Hawaiian-Emperor Seamount Chain? Thus, investigating the process responsible for long-lived episodic GVP volcanism provides the opportunity to evaluate this little understood process of rejuvenation in a physical setting very different to the Hawaiian-Emperor Chain (i.e. on/near spreading axis versus mid-plate). We consider here timing and geochemical information to test the various geodynamic models proposed to explain the origin of GVP hotspot volcanism, especially the possibility of rejuvenated phases that erupt long after initial shield-building.

An Efficient Randomized Algorithm for Real-Time Process Scheduling in PicOS Operating System

Science.gov (United States)

Helmy*, Tarek; Fatai, Anifowose; Sallam, El-Sayed

PicOS is an event-driven operating environment designed for use with embedded networked sensors. More specifically, it is designed to support the concurrency in intensive operations required by networked sensors with minimal hardware requirements. Existing process scheduling algorithms of PicOS; a commercial tiny, low-footprint, real-time operating system; have their associated drawbacks. An efficient, alternative algorithm, based on a randomized selection policy, has been proposed, demonstrated, confirmed for efficiency and fairness, on the average, and has been recommended for implementation in PicOS. Simulations were carried out and performance measures such as Average Waiting Time (AWT) and Average Turn-around Time (ATT) were used to assess the efficiency of the proposed randomized version over the existing ones. The results prove that Randomized algorithm is the best and most attractive for implementation in PicOS, since it is most fair and has the least AWT and ATT on average over the other non-preemptive scheduling algorithms implemented in this paper.

PiCO QL: A software library for runtime interactive queries on program data

Science.gov (United States)

Fragkoulis, Marios; Spinellis, Diomidis; Louridas, Panos

PiCO QL is an open source C/C++ software whose scientific scope is real-time interactive analysis of in-memory data through SQL queries. It exposes a relational view of a system's or application's data structures, which is queryable through SQL. While the application or system is executing, users can input queries through a web-based interface or issue web service requests. Queries execute on the live data structures through the respective relational views. PiCO QL makes a good candidate for ad-hoc data analysis in applications and for diagnostics in systems settings. Applications of PiCO QL include the Linux kernel, the Valgrind instrumentation framework, a GIS application, a virtual real-time observatory of stellar objects, and a source code analyser.

PiCO QL: A software library for runtime interactive queries on program data

Directory of Open Access Journals (Sweden)

Marios Fragkoulis

2016-01-01

Full Text Available Pico ql is an open source c/c++ software whose scientific scope is real-time interactive analysis of in-memory data through sql queries. It exposes a relational view of a system’s or application’s data structures, which is queryable through sql. While the application or system is executing, users can input queries through a web-based interface or issue web service requests. Queries execute on the live data structures through the respective relational views. pico ql makes a good candidate for ad-hoc data analysis in applications and for diagnostics in systems settings. Applications of pico ql include the Linux kernel, the Valgrind instrumentation framework, a gis application, a virtual real-time observatory of stellar objects, and a source code analyser.

Abrupt climatic changes as triggering mechanisms of massive volcanic collapses: examples from Mexico (Invited)

Science.gov (United States)

Capra, L.

2010-12-01

Climate changes have been considered to be a triggering mechanism for large magmatic eruptions. However they can also trigger volcanic collapses, phenomena that cause the destruction of the entire sector of a volcano, including its summit. During the past 30 ka, major volcanic collapses occurred just after main glacial peaks that ended with a rapid deglaciation. Glacial debuttressing, load discharge and fluid circulation coupled with the post-glacial increase of humidity and heavy rains can activate the failure of unstable edifices. Looking at the synchronicity of the maximum glaciations during the late Pleistocene and Holocene in the northern and southern hemispheres it is evident that several volcanic collapses are absent during a glacial climax, but start immediately after it during a period of rapid retreat. Several examples can be detected around the world and Mexico is not an exception. The 28 ka Nevado de Toluca volcanic collapse occurred during an intraglacial stage, under humid conditions as evidenced by paleoclimatic studies on lacustrine sediments of the area. The debris avalanche deposit associated to this event clearly shows evidence of a large amount of water into the mass previous to the failure that enhanced its mobility. It also contains peculiar, plastically deformed, m-sized fragment of lacustrine sediments eroded from glacial berms. The 17 ka BP collapse of the Colima Volcano corresponds to the initial stage of glacial retreat in Mexico after the Last Glacial Maximum (22-17.5ka). Also in this case the depositional sequence reflects high humidity conditions with voluminous debris flow containing a large amount logs left by pine trees. The occurrence of cohesive debris flows originating from the failure of a volcanic edifice can also reflect the climatic conditions, indicating important hydrothermal alteration and fluid circulation from ice-melting at an ice-capped volcano, as observed for example at the Pico de Orizaba volcano for the Tetelzingo

Volcanic features of Io

International Nuclear Information System (INIS)

Carr, M.H.; Masursky, H.; Strom, R.G.; Terrile, R.J.

1979-01-01

The volcanic features of Io as detected during the Voyager mission are discussed. The volcanic activity is apparently higher than on any other body in the Solar System. Its volcanic landforms are compared with features on Earth to indicate the type of volcanism present on Io. (U.K.)

El proceso de renovación urbana en La Boca: organizaciones barriales entre nuevos usos y viejos lugares

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Hilda Herzer

2007-06-01

úblicos. Viejos lugares tienen ahora un modo renovado de definir ese uso típico que siempre fue el turismo en La Boca. En efecto, buena parte de esos nuevos usos no han sido decididos ni incorporan a los vecinos de La Boca e introducen nuevos actores y lógicas en este escenario barrial. En este contexto, algunas instituciones están a favor de las transformaciones; otras, en contra y buena parte, no asume una voz nítida en el debate.

A Robust Controller Structure for Pico-Satellite Applications

DEFF Research Database (Denmark)

Kragelund, Martin Nygaard; Green, Martin; Kristensen, Mads

This paper describes the development of a robust controller structure for use in pico-satellite missions. The structure relies on unknown disturbance estimation and use of robust control theory to implement a system that is robust to both unmodeled disturbances and parameter uncertainties. As one...

Science development on volcanology flawed by the Spanish IGN

Science.gov (United States)

Pérez, Nemesio M.; Schmincke, Hans-Ulrich

2016-04-01

Scientists performing research activities in the field of volcanology, related more specifically to volcano monitoring in the Canary Islands, recently discovered that not all seismic events that occurred in the country had been listed in the Spanish National Seismic Catalogue and its related data base. The National Geographic Institute (IGN) is the legal Spanish institution in-charge of the National Seismic Catalogue, together with volcanic surveillance in Spain. It was therefore a huge surprise to discover that the number of seismic events registered in and around Tenerife Island in 2010, and according to the national catalogue, was only approximately 60, while the real number of seismic events recorded by the IGN in the region was 1,176. The existence of two different accounts of seismic activity registered by the IGN in and around Tenerife Island, keeping one for the public eye, while hiding the other one from even the scientific community, is not only illegal but also unscientific, hindering the progress of science. In addition, most importantly it is detrimental for timely forecasting of sudden/instantaneous dynamic events, such as major earthquakes and/or volcanic eruptions which might spell disaster for the population, the economy of the island, and severely impact tourism. This unethical behaviour by IGN's volcanological staff has already caused damage to open scientific discussions; a key parameter for scientific development. A scientific contribution was recently published using data from 15 years of research on diffuse CO2 emission monitoring from the summit cone of Teide volcano (Pérez et al., 2013). The seismic data that was used to discuss the observed temporal variations of the degassing pattern from Teide volcano came from the National Seismic Catalogue. In contrast it is obvious that the observed variations on diffuse CO2 emission from Teide volcano from 1997 to 2011 provided a better scientific explanation when using the real seismic data that

Non-moving Hadamard matrix diffusers for speckle reduction in laser pico-projectors

Science.gov (United States)

Thomas, Weston; Middlebrook, Christopher

2014-12-01

Personal electronic devices such as cell phones and tablets continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. This paper presents a binary diffuser known as a Hadamard matrix diffuser. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values measured showing good agreement with theory and simulated values.

Pico Lantern: Surface reconstruction and augmented reality in laparoscopic surgery using a pick-up laser projector.

Science.gov (United States)

Edgcumbe, Philip; Pratt, Philip; Yang, Guang-Zhong; Nguan, Christopher; Rohling, Robert

2015-10-01

The Pico Lantern is a miniature projector developed for structured light surface reconstruction, augmented reality and guidance in laparoscopic surgery. During surgery it will be dropped into the patient and picked up by a laparoscopic tool. While inside the patient it projects a known coded pattern and images onto the surface of the tissue. The Pico Lantern is visually tracked in the laparoscope's field of view for the purpose of stereo triangulation between it and the laparoscope. In this paper, the first application is surface reconstruction. Using a stereo laparoscope and an untracked Pico Lantern, the absolute error for surface reconstruction for a plane, cylinder and ex vivo kidney, is 2.0 mm, 3.0 mm and 5.6 mm, respectively. Using a mono laparoscope and a tracked Pico Lantern for the same plane, cylinder and kidney the absolute error is 1.4 mm, 1.5 mm and 1.5 mm, respectively. These results confirm the benefit of the wider baseline produced by tracking the Pico Lantern. Virtual viewpoint images are generated from the kidney surface data and an in vivo proof-of-concept porcine trial is reported. Surface reconstruction of the neck of a volunteer shows that the pulsatile motion of the tissue overlying a major blood vessel can be detected and displayed in vivo. Future work will integrate the Pico Lantern into standard and robot-assisted laparoscopic surgery. Copyright © 2015 Elsevier B.V. All rights reserved.

pico-PLAZA, a genome database of microbial photosynthetic eukaryotes.

Science.gov (United States)

Vandepoele, Klaas; Van Bel, Michiel; Richard, Guilhem; Van Landeghem, Sofie; Verhelst, Bram; Moreau, Hervé; Van de Peer, Yves; Grimsley, Nigel; Piganeau, Gwenael

2013-08-01

With the advent of next generation genome sequencing, the number of sequenced algal genomes and transcriptomes is rapidly growing. Although a few genome portals exist to browse individual genome sequences, exploring complete genome information from multiple species for the analysis of user-defined sequences or gene lists remains a major challenge. pico-PLAZA is a web-based resource (http://bioinformatics.psb.ugent.be/pico-plaza/) for algal genomics that combines different data types with intuitive tools to explore genomic diversity, perform integrative evolutionary sequence analysis and study gene functions. Apart from homologous gene families, multiple sequence alignments, phylogenetic trees, Gene Ontology, InterPro and text-mining functional annotations, different interactive viewers are available to study genome organization using gene collinearity and synteny information. Different search functions, documentation pages, export functions and an extensive glossary are available to guide non-expert scientists. To illustrate the versatility of the platform, different case studies are presented demonstrating how pico-PLAZA can be used to functionally characterize large-scale EST/RNA-Seq data sets and to perform environmental genomics. Functional enrichments analysis of 16 Phaeodactylum tricornutum transcriptome libraries offers a molecular view on diatom adaptation to different environments of ecological relevance. Furthermore, we show how complementary genomic data sources can easily be combined to identify marker genes to study the diversity and distribution of algal species, for example in metagenomes, or to quantify intraspecific diversity from environmental strains. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

Pico gauges for minimally invasive intracellular hydrostatic pressure measurements

DEFF Research Database (Denmark)

Knoblauch, Jan; Mullendore, Daniel L.; Jensen, Kaare Hartvig

2014-01-01

Intracellular pressure has a multitude of functions in cells surrounded by a cell wall or similar matrix in all kingdoms of life. The functions include cell growth, nastic movements, and penetration of tissue by parasites. The precise measurement of intracellular pressure in the majority of cells......, however, remains difficult or impossible due to their small size and/or sensitivity to manipulation. Here, we report on a method that allows precise measurements in basically any cell type over all ranges of pressure. It is based on the compression of nanoliter and picoliter volumes of oil entrapped...... in the tip of microcapillaries, which we call pico gauges. The production of pico gauges can be accomplished with standard laboratory equipment, and measurements are comparably easy to conduct. Example pressure measurements are performed on cells that are difficult or impossible to measure with other methods....

Matched-filtering generalized phase contrast using LCoS pico-projectors for beam-forming

OpenAIRE

Bañas, Andrew Rafael; Palima, Darwin; Glückstad, Jesper

2012-01-01

We report on a new beam-forming system for generating high intensity programmable optical spikes using so-called matched-filtering Generalized Phase Contrast (mGPC) applying two consumer handheld pico-projectors. Such a system presents a low-cost alternative for optical trapping and manipulation, optical lattices and other beam-shaping applications usually implemented with high-end spatial light modulators. Portable pico-projectors based on liquid crystal on silicon (LCoS) devices are used as...

Caracterização laboratorial das dislipidemias e o uso de fitoterápicos

Directory of Open Access Journals (Sweden)

Hanna Veloso Santos

2015-06-01

Full Text Available As plantas medicinais e os medicamentos fitoterápicos são amplamente utilizados no Brasil como alternativa terapêutica, principalmente por aqueles que estão em tratamento de doenças crônicas com outros medicamentos. Para demonstrar esse efeito, o presente estudo quer avaliar a eficácia de compostos fitoterápicos em portadores de dislipidemias, através de uma revisão de literatura. Os dados obtidos foram analisados e classificados em tipos de fitoterápicos utilizados; suas principais características; estudos que comprovem sua eficácia ou não; informações a respeito de efeitos colaterais; toxicidade e comercialização atual no uso das dislipidemias. Através dos artigos pesquisados, alguns autores asseguram a veracidade de que a farinha da casca de maracujá, extrato de berinjela e a farinha de abacate podem reduzir os níveis de Colesterol total, HDL e LDL, desde que associados as drogas farmacêuticas pré-existentes, embora outros autores concluam que o efeito causado pela ingestão do fitoterápicos não surtam resultados significativos.

Sources of Quaternary volcanism in the Itasy and Ankaratra volcanic fields, Madagascar

Science.gov (United States)

Rasoazanamparany, C.; Widom, E.; Kuentz, D. C.; Raharimahefa, T.; Rakotondrazafy, F. M. A.; Rakotondravelo, K. M.

2017-12-01

We present new major and trace element and Sr, Nd, Pb and Os isotope data for Quaternary basaltic lavas and tephra from the Itasy and Ankaratra volcanic fields, representing the most recent volcanism in Madagascar. Mafic magmas from Itasy and Ankaratra exhibit significant inter- and intra-volcanic field geochemical heterogeneity. The Itasy eruptive products range in composition from foidite to phonotephrite whereas Ankaratra lavas range from basanite to trachybasalts. Trace element signatures of samples from both volcanic fields are very similar to those of ocean island basalts (OIB), with significant enrichment in Nb and Ta, depletion in Rb, Cs, and K, and relatively high Nb/U and Ce/Pb. However, the Itasy volcanic rocks show enrichment relative to those of Ankaratra in most incompatible elements, indicative of a more enriched source and/or lower degrees of partial melting. Significant inter- and intra-volcanic field heterogeneity is also observed in Sr, Nd, Pb and Os isotope signatures. The Itasy volcanic rocks generally have less radiogenic Sr and Nd isotopic ratios but more radiogenic Pb isotopic signatures than the Ankaratra volcanic field. Together, the Itasy and Ankaratra volcanic rocks form a well-defined negative correlation in Sr vs. Pb isotopes that could be attributed to lithospheric contamination or variable degrees of mixing between distinct mantle sources. However, the lack of correlation between isotopes and indices of crustal contamination (e.g. MgO and Nb/U) are inconsistent with shallow lithospheric contamination, and instead suggest mixing between compositionally distinct mantle sources. Furthermore, although Sr-Pb isotope systematics are apparently consistent with mixing between two different sources, distinct trends in Sr vs. Nd isotopes displayed by samples from Itasy and Ankaratra, respectively, argue for more complex source mixing involving three or more sources. The current data demonstrate that although the Itasy and Ankaratra volcanic

Impacto do uso de psicotrópicos na dispersão do intervalo QT em pacientes adultos

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Bruno de Queiroz Claudio

2014-06-01

Full Text Available Fundamento: A dispersão do intervalo QT induzida por fármacos tem sido associada a arritmias ventriculares potencialmente fatais. Pouco se conhece sobre o uso de psicotrópicos, isolados ou em combinação com outros fármacos, na dispersão do QT. Objetivo: Avaliar o impacto do uso psicotrópicos na dispersão do intervalo QT em pacientes adultos. Métodos: Estudo de coorte observacional, envolvendo 161 pacientes hospitalizados em um departamento de emergência de hospital terciário, estratificados em usuários e não usuários de psicotrópicos. Dados demográficos, clínicos, laboratoriais e de fármacos em uso foram coletados à admissão, bem como o eletrocardiograma de 12 derivações, com a mensuração do intervalo e da dispersão do QT. Resultados: A dispersão do intervalo QT foi significativamente maior no grupo de usuário de psicotrópicos comparado ao grupo não usuário (69,25 ± 25,5 ms vs. 57,08 ± 23,4 ms; p = 0,002. O intervalo QT corrigido pela fórmula de Bazzett também se mostrou maior no grupo de usuário de psicotrópicos, com significância estatística (439,79 ± 31,14 ms vs. 427,71 ± 28,42 ms; p = 0,011. A análise por regressão linear mostrou associação positiva entre o número absoluto de psicotrópicos utilizados e a dispersão do intervalo QT, com r = 0,341 e p < 0,001. Conclusão: Na população amostral estudada, o uso de psicotrópicos se mostrou associado ao aumento da dispersão do intervalo QT, e esse incremento se acentuou em função do maior número de psicotrópicos utilizados.

Las consecuencias económicas de un nombre atípico. El caso colombiano

Directory of Open Access Journals (Sweden)

Alejandro Gaviria

2010-01-01

Full Text Available Este artículo examina las consecuencias en los ingresos laborales de tener un nombre atípico para el caso colombiano. La primera parte del artículo muestra que los jóvenes, hijos de padres no escolarizados, habitantes de zonas rurales y pertenecientes a minorías étnicas tienen una mayor probabilidad de tener un nombre atípico. La segunda parte muestra que el efecto de un nombre atípico en los salarios es grande (superior a 10% y que el mismo es mucho mayor para las personas escolarizadas que para los no escolarizadas. Los resultados sugieren la existencia de mecanismos de trasmisión intergeneracional distinto de los tradicionales (restricciones de crédito, mecanismos hereditarios, transferencias de ingresos, etc..

Busqueda, exhumación e identificación de represaliados de la Guerra Civil enterrados en el cementerio viejo de Palencia: el proyecto de la Carcavilla

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Almudena GARCÍA-RUBIO RUIZ

2017-01-01

Full Text Available Entre el año 2008 y 2013 se desarrolló el proyecto de exhumación e identificación de víctimas de la represión franquista en el Cementerio Viejo de Palencia, hoy parque de La Carcavilla. Se trataba de un caso complejo debido al tiempo transcurrido desde que ocurrieron los hechos, al elevado número de víctimas buscadas y a la falta de referencias espaciales tras la conversión del Cementerio Viejo en parque de recreo. El resultado fue la exhumación de 108 represaliados de los cuales 57 fueron identificados. La identificación de los restos, objetivo de la intervención, fue posible debido a un enfoque multidisciplinar basado en el cruce de información procedente de fuentes documentales, arqueológicas, osteológicas y genéticas. La reconstrucción de los eventos alrededor de la muerte durante la búsqueda y recuperación de los restos óseos, basada en la interpretación arqueológica y los datos de archivo, el análisis in situ de los mismos en el contexto en el que se encontraron y su posterior estudio en laboratorio, y finalmente el estudio genético, constituye un ejemplo práctico del crecimiento e intersección de la antropología forense con otras disciplinas.

Participatory ethnobotany in rural schools in Paso Viejo (Department of Cruz del Eje, Córdoba, Argentina

Directory of Open Access Journals (Sweden)

Gustavo Martínez

2016-07-01

Full Text Available We present a participatory ethnobotanical experience from the development of research projects, university outreach work, and university volunteer programs in the rural areas of Paso Viejo (Pedanía Pichanas, Cruz del Eje. The objective was to identify and save plant resources of cultural interest, in addition to discuss the community and educational processes that promote participatory research (citizen science with local actors. Five workshops were held on the different themes of ethnobotany, such as environmental interpretation, local productive practices, traditional food, veterinary medicine and forage plants. In the context of the local cultural context, we registered a total of 88 uses in 49 wild species and 3 cultivated species; 7 uses are associated with food, 19 with veterinary medicine, 32 with forage, and 30 with other uses. University students participated in the organization, planning, and preparation of the resources used as well as fieldwork registration and systematization of workshops. The study discusses how the construction of a dialogical experience promotes greater reciprocity in the process of collection of ethnobotanical data and knowledge, resulting in an educational and pedagogical process.

Using pico-LCoS SLMs for high speed cell sorting

DEFF Research Database (Denmark)

Bañas, Andrew Rafael; Aabo, Thomas; Palima, Darwin

2012-01-01

We propose the use of consumer pico projectors as cost effective spatial light modulators in cell sorting applications. The matched filtering Generalized Phase Contrast (mGPC) beam shaping method is used to produce high intensity optical spots for trapping and catapulting cells. A pico projector......’s liquid crystal on silicon (LCoS) chip was used as a binary phase spatial light modulator (SLM) wherein correlation target patterns are addressed. Experiments using the binary LCoS phase SLM with a fabricated Pyrex matched filter demonstrate the generation of intense optical spots that can potentially...... be used for cell sorting. Numerical studies also show mGPC’s robustness to phase aberrations in the LCoS device, and its ability to outperform a top hat beam with the same power....

Estudio médico deontológico del embarazo ectópico

OpenAIRE

Palma, J.A. (Jorge Arturo)

1990-01-01

Dentro de la temática general del aborto, el trabajo se centra hoy en el estudio moral del tratamiento médico del embarazo ectópico. El tema adquiere importancia si tenemos en cuenta que, según sea el enfoque y la solución que se dé a este problema, se abre o no un camino para la justificación moral del llamado 'aborto terapéutico'. Nos planteamos el problema de si la intervención quirúrgica por la cual se extirpa un embarazo ectópico, y de la que resulta la muerte del...

ANTICONCEPCIÓN HORMONAL DE EMERGENCIA Y EMBARAZO ECTÓPICO: CASO CLÍNICO

OpenAIRE

Rosa W,Guillermo; Anrinque Ch,Denisse; Rodríguez J,Paola

2009-01-01

El riesgo de embarazo ectópico después de anticoncepción de emergencia es un hecho conocido y con el aumento de la demanda por este método, es esperable un mayor número de casos en el futuro. Se presenta un caso de embarazo ectópico después del fracaso de la anticoncepción de emergencia con levonorgestrel. The risk of ectopic pregnancy after emergency contraception is known and with the increased use of this treatment, we might expect more cases in the future. One case of ectopic pregnancy...

Efectos del tratamiento con Compvit B, ácido orótico o la combinación de ambos sobre la recuperación de la memoria espacial en ratas con lesión de fimbria-fornix

OpenAIRE

González Gay, Olivia Teresa; Almaguer Melián, William; Ramírez Figueredo, Magalys; Vallejo Morales, Araceli; Bergado Rosado, Jorge Alberto

2011-01-01

Las vitaminoterapias han sido ampliamente utilizadas en neurología para el tratamiento de neuritis o la correción de déficit metabólicos. En Cuba, se produce desde hace algunos años el preparado vitamínico Compvit®, que contiene vitaminas B1, B6 y B12. El ácido orótico, también llamado vitamina B13, es un producto natural que ha mostrado acciones como nootrópico en estudios con animales jóvenes y viejos que acusan deterioro cognitivo. En el presente trabajo se reportan los resultados de un es...

Cyberbullying

OpenAIRE

Ortega Ruiz, Rosario; Calmaestra Villén, Juan; Mora Merchán, Joaquín Antonio

2008-01-01

El problema de la violencia escolar y el bullying es ya un fenómeno conocido por la sociedad y un viejo tópico investigador. Pero las vías por la que se produce el bullying han evolucionado en el tiempo y han surgido nuevas formas de intimidación, acoso y malos tratos. Una de estas formas es conocida como cyberbullying. Este artículo explora el cyberbullying usando un cuestionario específico a un total de 830 escolares con edades comprendidas entre los 12 y 18 años. Los resulta...

La red de Matrix. ¿En los límites de lo posible?

OpenAIRE

Petrizzo Páez, María Ángela; Maya Jariego, Isidro

2005-01-01

La trilogía de Matrix ofrece una poderosa metáfora sobre la convergencia hombremáquina. Los resquicios de esa interface llevan implícita una dualidad que permite presentar el viejo tópico de la confusión entre fantasía y realidad en términos de "espejismos virtuales", como es propio de la era de la Inteligencia Artificial. Pero la navegación en estructuras paralelas a la realidad, así como la íntima conexión entre el hombre y los computadores, tienen referencias reales. Los buscadores de Inte...

Volcanic sulfur dioxide index and volcanic explosivity index inferred from eruptive volume of volcanoes in Jeju Island, Korea: application to volcanic hazard mitigation

Science.gov (United States)

Ko, Bokyun; Yun, Sung-Hyo

2016-04-01

Jeju Island located in the southwestern part of Korea Peninsula is a volcanic island composed of lavaflows, pyroclasts, and around 450 monogenetic volcanoes. The volcanic activity of the island commenced with phreatomagmatic eruptions under subaqueous condition ca. 1.8-2.0 Ma and lasted until ca. 1,000 year BP. For evaluating volcanic activity of the most recently erupted volcanoes with reported age, volcanic explosivity index (VEI) and volcanic sulfur dioxide index (VSI) of three volcanoes (Ilchulbong tuff cone, Songaksan tuff ring, and Biyangdo scoria cone) are inferred from their eruptive volumes. The quantity of eruptive materials such as tuff, lavaflow, scoria, and so on, is calculated using a model developed in Auckland Volcanic Field which has similar volcanic setting to the island. The eruptive volumes of them are 11,911,534 m3, 24,987,557 m3, and 9,652,025 m3, which correspond to VEI of 3, 3, and 2, respectively. According to the correlation between VEI and VSI, the average quantity of SO2 emission during an eruption with VEI of 3 is 2-8 × 103 kiloton considering that the island was formed under intraplate tectonic setting. Jeju Island was regarded as an extinct volcano, however, several studies have recently reported some volcanic eruption ages within 10,000 year BP owing to the development in age dating technique. Thus, the island is a dormant volcano potentially implying high probability to erupt again in the future. The volcanoes might have explosive eruptions (vulcanian to plinian) with the possibility that SO2 emitted by the eruption reaches stratosphere causing climate change due to backscattering incoming solar radiation, increase in cloud reflectivity, etc. Consequently, recommencement of volcanic eruption in the island is able to result in serious volcanic hazard and this study provides fundamental and important data for volcanic hazard mitigation of East Asia as well as the island. ACKNOWLEDGMENTS: This research was supported by a grant [MPSS

A Feasibility Study of Power Generation from Sewage Using a Hollowed Pico-Hydraulic Turbine

OpenAIRE

Tomomi Uchiyama; Satoshi Honda; Tomoko Okayama; Tomohiro Degawa

2016-01-01

This study is concerned with the feasibility of power generation using a pico-hydraulic turbine from sewage flowing in pipes. First, the sewage flow rate at two connection points to the Toyogawa River-Basin Sewerage, Japan, was explored for over a year to elucidate the hydraulic energy potential of the sewage. Second, the performance of the pico-hydraulic turbine was investigated via laboratory experiments that supposed the turbine to be installed in the sewage pipe at the connection points. ...

El cuento en Colombia. Viento de trópico

Directory of Open Access Journals (Sweden)

Javier Arias Ramírez

1961-01-01

Full Text Available No sería "Viento de Trópico", sino Cuentos Intensos, el nombre del libro que acaba de publicar José Francisco Socarrás. Hay tal dramatismo y tal densidad psicológica, propios de quien ha vivido en continuo y fatigoso indagar de la conciencia.

Guidance, Navigation, and Control System for Maneuverable Pico-Satellites, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A compact, low-power GN&C system is essential to the success of pico-satellite Automated Rendezvous and Docking (AR&D). Austin Satellite Design (ASD)...

Volcanic Alert System (VAS) developed during the (2011-2013) El Hierro (Canary Islands) volcanic process

Science.gov (United States)

Ortiz, Ramon; Berrocoso, Manuel; Marrero, Jose Manuel; Fernandez-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Garcia, Alicia

2014-05-01

In volcanic areas with long repose periods (as El Hierro), recently installed monitoring networks offer no instrumental record of past eruptions nor experience in handling a volcanic crisis. Both conditions, uncertainty and inexperience, contribute to make the communication of hazard more difficult. In fact, in the initial phases of the unrest at El Hierro, the perception of volcanic risk was somewhat distorted, as even relatively low volcanic hazards caused a high political impact. The need of a Volcanic Alert System became then evident. In general, the Volcanic Alert System is comprised of the monitoring network, the software tools for the analysis of the observables, the management of the Volcanic Activity Level, and the assessment of the threat. The Volcanic Alert System presented here places special emphasis on phenomena associated to moderate eruptions, as well as on volcano-tectonic earthquakes and landslides, which in some cases, as in El Hierro, may be more destructive than an eruption itself. As part of the Volcanic Alert System, we introduce here the Volcanic Activity Level which continuously applies a routine analysis of monitoring data (particularly seismic and deformation data) to detect data trend changes or monitoring network failures. The data trend changes are quantified according to the Failure Forecast Method (FFM). When data changes and/or malfunctions are detected, by an automated watchdog, warnings are automatically issued to the Monitoring Scientific Team. Changes in the data patterns are then translated by the Monitoring Scientific Team into a simple Volcanic Activity Level, that is easy to use and understand by the scientists and technicians in charge for the technical management of the unrest. The main feature of the Volcanic Activity Level is its objectivity, as it does not depend on expert opinions, which are left to the Scientific Committee, and its capabilities for early detection of precursors. As a consequence of the El Hierro

Volcanic hazards to airports

Science.gov (United States)

Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.

2009-01-01

Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

The Online GVP/USGS Weekly Volcanic Activity Report: Providing Timely Information About Worldwide Volcanism

Science.gov (United States)

Mayberry, G. C.; Guffanti, M. C.; Luhr, J. F.; Venzke, E. A.; Wunderman, R. L.

2001-12-01

The awesome power and intricate inner workings of volcanoes have made them a popular subject with scientists and the general public alike. About 1500 known volcanoes have been active on Earth during the Holocene, approximately 50 of which erupt per year. With so much activity occurring around the world, often in remote locations, it can be difficult to find up-to-date information about current volcanism from a reliable source. To satisfy the desire for timely volcano-related information the Smithsonian Institution and US Geological Survey combined their strengths to create the Weekly Volcanic Activity Report. The Smithsonian's Global Volcanism Program (GVP) has developed a network of correspondents while reporting worldwide volcanism for over 30 years in their monthly Bulletin of the Global Volcanism Network. The US Geological Survey's Volcano Hazards Program studies and monitors volcanoes in the United States and responds (upon invitation) to selected volcanic crises in other countries. The Weekly Volcanic Activity Report is one of the most popular sites on both organization's websites. The core of the Weekly Volcanic Activity Report is the brief summaries of current volcanic activity around the world. In addition to discussing various types of volcanism, the summaries also describe precursory activity (e.g. volcanic seismicity, deformation, and gas emissions), secondary activity (e.g. debris flows, mass wasting, and rockfalls), volcanic ash hazards to aviation, and preventative measures. The summaries are supplemented by links to definitions of technical terms found in the USGS photoglossary of volcano terms, links to information sources, and background information about reported volcanoes. The site also includes maps that highlight the location of reported volcanoes, an archive of weekly reports sorted by volcano and date, and links to commonly used acronyms. Since the Weekly Volcanic Activity Report's inception in November 2000, activity has been reported at

Matched-filtering generalized phase contrast using LCoS pico-projectors for beam-forming.

Science.gov (United States)

Bañas, Andrew; Palima, Darwin; Glückstad, Jesper

2012-04-23

We report on a new beam-forming system for generating high intensity programmable optical spikes using so-called matched-filtering Generalized Phase Contrast (mGPC) applying two consumer handheld pico-projectors. Such a system presents a low-cost alternative for optical trapping and manipulation, optical lattices and other beam-shaping applications usually implemented with high-end spatial light modulators. Portable pico-projectors based on liquid crystal on silicon (LCoS) devices are used as binary phase-only spatial light modulators by carefully setting the appropriate polarization of the laser illumination. The devices are subsequently placed into the object and Fourier plane of a standard 4f-setup according to the mGPC spatial filtering configuration. Having a reconfigurable spatial phase filter, instead of a fixed and fabricated one, allows the beam shaper to adapt to different input phase patterns suited for different requirements. Despite imperfections in these consumer pico-projectors, the mGPC approach tolerates phase aberrations that would have otherwise been hard to overcome by standard phase projection. © 2012 Optical Society of America

Laia de Camões — O épico

Directory of Open Access Journals (Sweden)

Lygia Alvares Correa

1951-06-01

Full Text Available CIDADE ('liernatii. Laia de Camões — O épico, Revista da Faculdade  de Letras. Tomo XVI. 2.°' série. ns. I e 2. Universidade de Lisboa  1950. (Primeiro Parágrafo do Artigo Este segundo volume que a respeito de Camões escreve o Prof. Cidade surge 14 anos após, "Luiz de Camões".

Deforestation carbon dynamics and sustainable mitigation measures in Costa Rica: the Puerto Viejo de Sarapiqui case study

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Azofeifa, G A; Quesade-Mateo, C [Unidersidad de Costa Rica, San Jose (Costa Rica). Centro para Investigaciones en Desarrollo Sostenible

1995-11-01

The definition of mitigation policies and implementation projects in developing countries must be based on solid scientific knowledge foundations. This knowledge basis must not only provide information on the response of physical systems, but must consider, besides, the social forces that induce the response of natural systems. In the present article, the role played by science and technology in the definition of abatement policies is analyzed by means of a case-study in the Puerto Viejo de Sarapiqui area, in Costa Rica. Satellite information and geographical information systems are combined in order to understand the forces generating a change in the use of land in this area, as well in the building of a data-base which may permit the definition of long-term policies. It is concluded in this article that the success of any policy or program will only be achieved if these are included within a referential framework which is related to a strategy for a country`s coherent and sustainable development. 20 refs., 3 figs.

Simulation of excitation and propagation of pico-second ultrasound

International Nuclear Information System (INIS)

Yang, Seung Yong; Kim, No Hyu

2016-01-01

This paper presents an analytic and numerical simulation of the generation and propagation of pico-second ultrasound with nano-scale wavelength, enabling the production of bulk waves in thin films. An analytic model of laser-matter interaction and elasto-dynamic wave propagation is introduced to calculate the elastic strain pulse in microstructures. The model includes the laser-pulse absorption on the material surface, heat transfer from a photon to the elastic energy of a phonon, and acoustic wave propagation to formulate the governing equations of ultra-short ultrasound. The excitation and propagation of acoustic pulses produced by ultra-short laser pulses are numerically simulated for an aluminum substrate using the finite-difference method and compared with the analytical solution. Furthermore, Fourier analysis was performed to investigate the frequency spectrum of the simulated elastic wave pulse. It is concluded that a pico-second bulk wave with a very high frequency of up to hundreds of gigahertz is successfully generated in metals using a 100-fs laser pulse and that it can be propagated in the direction of thickness for thickness less than 100 nm

Simulation of excitation and propagation of pico-second ultrasound

Energy Technology Data Exchange (ETDEWEB)

Yang, Seung Yong; Kim, No Hyu [Dept. of Mechanical Engineering, Korea University of Technology and Education, Chunan (Korea, Republic of)

2016-12-15

This paper presents an analytic and numerical simulation of the generation and propagation of pico-second ultrasound with nano-scale wavelength, enabling the production of bulk waves in thin films. An analytic model of laser-matter interaction and elasto-dynamic wave propagation is introduced to calculate the elastic strain pulse in microstructures. The model includes the laser-pulse absorption on the material surface, heat transfer from a photon to the elastic energy of a phonon, and acoustic wave propagation to formulate the governing equations of ultra-short ultrasound. The excitation and propagation of acoustic pulses produced by ultra-short laser pulses are numerically simulated for an aluminum substrate using the finite-difference method and compared with the analytical solution. Furthermore, Fourier analysis was performed to investigate the frequency spectrum of the simulated elastic wave pulse. It is concluded that a pico-second bulk wave with a very high frequency of up to hundreds of gigahertz is successfully generated in metals using a 100-fs laser pulse and that it can be propagated in the direction of thickness for thickness less than 100 nm.

Simulation of excitation and propagation of pico-second ultrasound

Energy Technology Data Exchange (ETDEWEB)

Yang, Seung Yong; Kim, No Kyu [Dept. of Mechanical Engineering, Korea University of Technology and Education, Chunan (Korea, Republic of)

2014-12-15

This paper presents an analytic and numerical simulation of the generation and propagation of pico-second ultrasound with nano-scale wavelength, enabling the production of bulk waves in thin films. An analytic model of laser-matter interaction and elasto-dynamic wave propagation is introduced to calculate the elastic strain pulse in microstructures. The model includes the laser-pulse absorption on the material surface, heat transfer from a photon to the elastic energy of a phonon, and acoustic wave propagation to formulate the governing equations of ultra-short ultrasound. The excitation and propagation of acoustic pulses produced by ultra-short laser pulses are numerically simulated for an aluminum substrate using the finite-difference method and compared with the analytical solution. Furthermore, Fourier analysis was performed to investigate the frequency spectrum of the simulated elastic wave pulse. It is concluded that a pico-second bulk wave with a very high frequency of up to hundreds of gigahertz is successfully generated in metals using a 100-fs laser pulse and that it can be propagated in the direction of thickness for thickness less than 100 nm.

Volcanic signals in oceans

KAUST Repository

Stenchikov, Georgiy L.

2009-08-22

Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

A light left in the dark: The practice and politics of pico-hydropower in the Lao PDR

International Nuclear Information System (INIS)

Smits, Mattijs; Bush, Simon R.

2010-01-01

The article describes the widespread use of an estimated 60,000 low-head pico-hydropower turbines and well-developed networks of supply and support in the Northern part of the Lao People's Democratic Republic (Lao PDR). This apparent widespread use is contrasted with the policy narratives of key actors in the government, multilateral organisations and the private sector which show an often simplified and overly negative attitude towards pico-hydropower. Based on empirical research carried out in three upland districts and the capital, Vientiane, the paper critically investigates the apparent disjuncture between policy and practice by placing pico-hydropower within the broader political context of rural electrification in the Lao PDR. It is argued that the neglect of pico-hydropower and other off-grid household electrification technologies is a result of an endemic lack of information on which to base policy decisions, the orientation of the government to facilitate large scale foreign investment in large hydropower dams, the universal applicability of solar home systems, and the broader state agenda of centralisation and control over service provision to remote upland areas.

Pico-solar electric systems the earthscan expert guide to the technology and emerging market

CERN Document Server

Keane, John

2014-01-01

This book provides a comprehensive overview of the technology behind the pico-solar revolution and offers guidance on how to test and choose quality products. The book also discusses how pioneering companies and initiatives are overcoming challenges to reach scale in the marketplace, from innovative distribution strategies to reach customers in rural India and Tanzania, to product development in Cambodia, product assembly in Mozambique and the introduction of 'pay as you go' technology in Kenya.Pico-solar is a new category of solar electric system which has the potential to transform the lives

¿Teatro épico hoy? Paradojas radicales y tres dramas en español

OpenAIRE

García Barrientos, José Luis

2013-01-01

[ES] A la luz de las dos paradojas que se advierten en la raíz misma del llamado teatro épico, la política, en cuanto se presenta al servicio de una clase, el proletariado, que no puede sostenerlo, y la narrativa, derivada de la contradicción entre los dos modos de imitación aristotélicos, se defiende la tesis de que en la actualidad siguen plenamente vigentes las aportaciones estéticas (“narrativas”) del teatro épico, pero no el dogmatismo político revolucionario en que supues...

Analgésicos tópicos

Directory of Open Access Journals (Sweden)

Murilo Pereira Flores

2012-04-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: O tratamento da dor envolve a utilização de analgésicos opioides, analgésicos comuns, anti-inflamatórios não hormonais (AINH's e analgésicos adjuvantes. Tradicionalmente, estes fármacos são administrados por via sistêmica ou no neuroeixo. Entretanto, quando aplicados por estas vias, estão associados a efeitos colaterais importantes, os quais podem inviabilizar o seu uso. A administração tópica de analgésicos é uma alternativa. O objetivo deste trabalho é discutir os analgésicos tópicos, seus mecanismos de ação e eficácia clínica. CONTEÚDO: Trata-se de um trabalho de revisão que aborda a utilização tópica de anestésicos locais, capsaicina, clonidina, antidepressivos tricíclicos, cetamina, opioides e canabinoides, discutindo o seu mecanismo de ação e a sua eficácia. CONCLUSÕES: Os analgésicos tópicos são promissores como estratégia para o tratamento da dor, já que estão associados à menor incidência de efeitos colaterais. O benefício dos anestésicos locais, dos AINH's e da capsaicina está bem estabelecido, entretanto, a eficácia de clonidina, antidepressivos tricíclicos, cetamina, opioides e canabinoides ainda é questionável. Trabalhos demonstram que a abordagem multimodal é uma alternativa, porém estudos são necessários para confirmar esta hipótese.

The Volcanism Ontology (VO): a model of the volcanic system

Science.gov (United States)

Myer, J.; Babaie, H. A.

2017-12-01

We have modeled a part of the complex material and process entities and properties of the volcanic system in the Volcanism Ontology (VO) applying several top-level ontologies such as Basic Formal Ontology (BFO), SWEET, and Ontology of Physics for Biology (OPB) within a single framework. The continuant concepts in BFO describe features with instances that persist as wholes through time and have qualities (attributes) that may change (e.g., state, composition, and location). In VO, the continuants include lava, volcanic rock, and volcano. The occurrent concepts in BFO include processes, their temporal boundaries, and the spatio-temporal regions within which they occur. In VO, these include eruption (process), the onset of pyroclastic flow (temporal boundary), and the space and time span of the crystallization of lava in a lava tube (spatio-temporal region). These processes can be of physical (e.g., debris flow, crystallization, injection), atmospheric (e.g., vapor emission, ash particles blocking solar radiation), hydrological (e.g., diffusion of water vapor, hot spring), thermal (e.g., cooling of lava) and other types. The properties (predicates) relate continuants to other continuants, occurrents to continuants, and occurrents to occurrents. The ontology also models other concepts such as laboratory and field procedures by volcanologists, sampling by sensors, and the type of instruments applied in monitoring volcanic activity. When deployed on the web, VO will be used to explicitly and formally annotate data and information collected by volcanologists based on domain knowledge. This will enable the integration of global volcanic data and improve the interoperability of software that deal with such data.

Volcanic signals in oceans

KAUST Repository

Stenchikov, Georgiy L.; Delworth, Thomas L.; Ramaswamy, V.; Stouffer, Ronald J.; Wittenberg, Andrew; Zeng, Fanrong

2009-01-01

Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean

ANÁLISIS CARIOTÍPICO DE CAPSICUM PUBESCENS (SOLANACEAE "ROCOTO"

Directory of Open Access Journals (Sweden)

Misael Guevara

2014-06-01

Full Text Available Análisis cariotípico de Capsicum pubescens R&P (Solanaceae. Los cromosomas han sido descritos, comparados y dibujados, usando una técnica de coloración modificada, C. pubescens tiene un número cromosómico diploide 2n = 24, de los cuales 11 pares son metacéntricos y 1 par submetacéntrico.

CONSULTA DE ENFERMAGEM EM GERIATRIA: TÓPICOS A SEREM ABORDADOS NO EXAME FÍSICO — PARTE II.

Directory of Open Access Journals (Sweden)

Maria Coeli Campedelli

Full Text Available Neste trabalho são apresentados os itens considerados importantes para o exame físico do indivíduo idoso, além de outros tópicos que são fundamentais para a consulta de Enfermagem, complementando o artigo intitulado: "Consulta de Enfermagem em Geriatria: tópicos a serem abordados na Entrevista — parte I".

On the detectability of Teide volcano magma chambers (Tenerife, Canary Islands) with magnetotelluric data

Science.gov (United States)

Piña-Varas, Perla; Ledo, Juanjo; Queralt, Pilar; Marcuello, Alex; Perez, Nemesio

2018-01-01

Tenerife has been the subject of numerous studies covering a wide range of fields. Many studies have been focused on characterising the magmatic plumbing system. Even so, a controversy still exists regarding the location and size of the current magma chambers. Several magnetotelluric (MT) surveys have been carried out in the island, but no conductivity anomalies associated with the chambers have been detected. We report the results of a set of tests conducted against the 3-D resistivity model of the island, to determine the characteristics of the detectable chambers with the MT data. The most remarkable results indicate that the MT dataset is incompatible with a large-scale mafic reservoir located at shallower depths than 8 km b.s.l. However, shallower phonolitic chambers smaller than 3 × 3 × 1 km3 could be undetected by the existing MT sites and new data should be acquired to confirm or not their existence. This new information is essential in volcanic islands like Tenerife, since many volcanic hazards are related to the size and depth of the sources of magma. Additionally, a joint interpretation of the obtained results together with other information is summarised in a hypothetical model, allowing us to better understand the internal structure of the island.[Figure not available: see fulltext.

Poisoning histories in the Italian renaissance: The case of Pico Della Mirandola and Angelo Poliziano.

Science.gov (United States)

Gallello, Gianni; Cilli, Elisabetta; Bartoli, Fulvio; Andretta, Massimo; Calcagnile, Lucio; Pastor, Agustin; de la Guardia, Miguel; Serventi, Patrizia; Marino, Alberto; Benazzi, Stefano; Gruppioni, Giorgio

2018-05-01

Giovanni Pico della Mirandola and Angelo Poliziano were two of the most important humanists of the Italian Renaissance. They died suddenly in 1494 and their deaths have been for centuries a subject of debate. The exhumation of their remains offered the opportunity to study the cause of their death through a multidisciplinary research project. Anthropological analyses, together with documentary evidences, radiocarbon dating and ancient DNA analysis supported the identification of the remains attributed to Pico. Macroscopic examination did not reveal paleopathological lesions or signs related to syphilis. Heavy metals analysis, carried out on bones and mummified tissues, showed that in Pico's remains there were potentially lethal levels of arsenic, supporting the philosopher's poisoning theory reported by documentary sources. The arsenic concentrations obtained from analysis of Poliziano's remains, are probably more related to an As chronic exposure or diagenetic processes rather than poisoning. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Candidate constructional volcanic edifices on Mercury

OpenAIRE

Wright, J.; Rothery, D. A.; Balme, M. R.; Conway, S. J.

2018-01-01

[Introduction] Studies using MESSENGER data suggest that Mercury’s crust is predominantly a product of effusive volcanism that occurred in the first billion years following the planet’s formation. Despite this planet-wide effusive volcanism, no constructional volcanic edifices, characterized by a topographic rise, have hitherto been robustly identified on Mercury, whereas constructional volcanoes are common on other planetary bodies in the solar system with volcanic histories. Here, we descri...

Disruptive event analysis: volcanism and igneous intrusion

International Nuclear Information System (INIS)

Crowe, B.M.

1980-08-01

An evaluation is made of the disruptive effects of volcanic activity with respect to long term isolation of radioactive waste through deep geologic storage. Three major questions are considered. First, what is the range of disruption effects of a radioactive waste repository by volcanic activity. Second, is it possible, by selective siting of a repository, to reduce the risk of disruption by future volcanic activity. And third, can the probability of repository disruption by volcanic activity be quantified. The main variables involved in the evaluation of the consequences of repository disruption by volcanic activity are the geometry of the magma-repository intersection (partly controlled by depth of burial) and the nature of volcanism. Potential radionuclide dispersal by volcanic transport within the biosphere ranges in distance from several kilometers to global. Risk from the most catastrophic types of eruptions can be reduced by careful site selection to maximize lag time prior to the onset of activity. Certain areas or volcanic provinces within the western United States have been sites of significant volcanism and should be avoided as potential sites for a radioactive waste repository. Examples of projection of future sites of active volcanism are discussed for three areas of the western United States. Probability calculations require two types of data: a numerical rate or frequency of volcanic activity and a numerical evaluation of the areal extent of volcanic disruption for a designated region. The former is clearly beyond the current state of art in volcanology. The latter can be approximated with a reasonable degree of satisfaction. In this report, simplified probability calculations are attempted for areas of past volcanic activity

238U-230Th-226Ra systematics applied to the active oceanic volcanism. Constraints on the duration and processes of magmas formation

International Nuclear Information System (INIS)

Claude-Ivana, Ch.

1997-02-01

The development of a new precise analytical technique for measuring radioactive disequilibria by TIMS has enabled to put constraints on both the extend and time scale of incompatible element fractionation during magma formation in oceanic islands. Three different settings have been studied: the Grande Comore volcanoes (Comores archipelago), Tenerife and Lanzarote volcanism (Canary islands) and four islands within the Azores: Sao Miguel, Terceira, Pico and Faial islands. The Comores and Canaries archipelagoes are both lying on an old thick oceanic lithosphere. The detailed case in Grande Comore shows evidence for a process of interaction of the Comore plume with the underlying lithosphere. In the Canaries, the lithosphere also contributes to lava formation either during the differentiation (in Tenerife) or during mantle melting (in Lanzarote). Within the Azores, U-series measurements reveal large geochemical and isotopic variations between the different islands that we interpret as reflecting heterogeneities in the Azore plume. In particular, the U-Th fractionation in Sao Miguel volcanics is though to result from melting of an hydrous sediment-bearing mantle. The magma transit times have been found to be very short (1000 yr) in all the basaltic series. This very rapid migration of the melts is an evidence for the absence of large magma chamber and for processes of fracturing during melt transports. However, this model does not apply in the case of the very evolved volcanic series in Tenerife island (Canaries) where transit times of c.a. 100000 yr indicate the presence of a large magmatic reservoir. (author)

Inotrópicos en el postoperatorio de cirugía cardiovascular: estudio de corte transversal

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Luis A. Muñoz

2014-07-01

Conclusión: En casi la mitad de los pacientes en postoperatorio de cirugía cardiovascular se utilizó un agente inotrópico, de los cuales la adrenalina fue la más frecuente, seguida de la norepinefrina; el inodilatador utilizado fue la dobutamina. No se utilizaron inotrópicos sensibilizadores del calcio y en baja frecuencia inhibidores de la fosfodiesterasa III con resultados similares en cuanto a estancia en la unidad de cuidados intensivos y mortalidad respecto a estudios en otras poblaciones.

The herpetofauna of Parque Nacional Pico Bonito, Honduras

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James R. McCranie

2005-10-01

Full Text Available Seventy-three species of amphibians and reptiles (six salamanders, 20 anurans, 20 lizards, and 27 snakes are known from Parque Nacional Pico Bonito, Honduras. The physiography, climate, vegetation, and microhabitats of the park are briefly described. Forty-four species are recorded from Lowland Moist Forest, 45 from Premontane Wet Forest, and 14 from Lower Montane Wet Forest. The primary microhabitat and relative abundance of each species are indicated and population declines are discussed.

DOS SOCIALISMOS UTÓPICO E REVOLUCIONÁRIO À ECONOMIA SOLIDÁRIA

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Miriam Hermi Zaar

2013-01-01

Full Text Available Gran parte de las características que atribuimos a las experiencias asociadas a la economía solidaria no son recientes, están imbuidas de conceptos desarrollados por teóricos del siglo XIX que formaron parte de corrientes filosóficas como el liberalismo, el socialismo utópico y el socialismo revolucionario. A ellas contribuyeron, por un lado, las ideas y las obras de los socialistas utópicos Saint Simon, Charles Fourrier y Robert Owen; y por otro, las teorías revolucionarias desarrolladas por Proudhon, Bakunin, Kropotkin, Marx y Lenin. Para entender este proceso elaboramos una reflexión teórica sobre los ideales que fomentaron las experiencias asociativas en este último siglo y medio, que continúan presentes en los recientes movimientos sociales que se caracterizan por la práctica de la economía solidaria.

Digital and preliminary bedrock geologic map of the Pico Peak quadrangle, Vermont

Data.gov (United States)

Vermont Center for Geographic Information — Digital Data from VG98-226A Walsh, G. J., and Ratcliffe, N.M., 1998,�Digital and preliminary bedrock geologic map of the Pico Peak quadrangle, Vermont: USGS...

Generalized Phase Contrast with matched filtering using LCoS pico-projectors

DEFF Research Database (Denmark)

Bañas, Andrew Rafael; Palima, Darwin; Glückstad, Jesper

2012-01-01

, optical lattices and other beam shaping applications usually implemented with high-end spatial light modulators. Portable pico-projectors based on liquid crystal on silicon (LCoS) devices were used as binary phase-only spatial light modulators by setting the appropriate polarization of the illumination...

Review of the efficacy of placebo in comparative clinical trials between typical and atypical antipsychotics Revisão da eficácia do placebo nos ensaios clínicos que comparam antipsicóticos típicos e atípicos

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Irismar Reis de Oliveira

2009-03-01

Full Text Available OBJECTIVE: To review the efficacy of placebo in comparison with atypical and typical antipsychotics for the treatment of schizophrenia and schizoaffective disorder and to evaluate the pertinence of using placebo in clinical trials with antipsychotics. METHOD: Trials in which the atypical antipsychotics were compared with typical antipsychotics and placebo were included. A search was conducted using the terms "amisulpride", "aripiprazole", "clozapine", "olanzapine", "quetiapine", "risperidone", "sertindole", "ziprasidone" and "zotepine". Main efficacy parameters were calculated using the proportion of "events" (defined as a deterioration or lack of improvement by at least 20% in Positive and Negative Syndrome Scale or Brief Psychiatric Rating Scale and the pooled relative risk with random effects, with their respective 95% confidence intervals. We also calculated the necessary sample sizes in studies in which the study drug is compared to a typical antipsychotic or placebo. RESULTS: The pooled efficacy rates observed were 40.8%, 34.9% and 21.3% for the atypical antipsychotics, typical antipsychotics and placebo, respectively. One hundred and sixty six patients would have to be included when a new drug is compared with placebo if calculation is based on a difference of 20% found between the atypical antipsychotic and placebo and 2,054 if the difference sought were that found between the atypical antipsychotic and the typical antipsychotic, i.e. 6%. The estimated therapeutic failures would be 115 of the 166 patients when the study drug is compared with placebo, and 1,274 failures in the 2,054 patients when the study drug is compared to the typical antipsychotic. CONCLUSIONS: Placebo controlled studies may reduce the number of individuals exposed to the harmful effects of ineffective drugs.OBJETIVO: Revisar a eficácia do placebo em comparação com a dos antipsicóticos atípicos e típicos no tratamento da esquizofrenia e do transtorno

Using Volcanic Lightning Measurements to Discern Variations in Explosive Volcanic Activity

Science.gov (United States)

Behnke, S. A.; Thomas, R. J.; McNutt, S. R.; Edens, H. E.; Krehbiel, P. R.; Rison, W.

2013-12-01

VHF observations of volcanic lightning have been made during the recent eruptions of Augustine Volcano (2006, Alaska, USA), Redoubt Volcano (2009, Alaska, USA), and Eyjafjallajökull (2010, Iceland). These show that electrical activity occurs both on small scales at the vent of the volcano, concurrent with an eruptive event and on large scales throughout the eruption column during and subsequent to an eruptive event. The small-scale discharges at the vent of the volcano are often referred to as 'vent discharges' and are on the order of 10-100 meters in length and occur at rates on the order of 1000 per second. The high rate of vent discharges produces a distinct VHF signature that is sometimes referred to as 'continuous RF' radiation. VHF radiation from vent discharges has been observed at sensors placed as far as 100 km from the volcano. VHF and infrasound measurements have shown that vent discharges occur simultaneously with the onset of eruption, making their detection an unambiguous indicator of explosive volcanic activity. The fact that vent discharges are observed concurrent with explosive volcanic activity indicates that volcanic ejecta are charged upon eruption. VHF observations have shown that the intensity of vent discharges varies between eruptive events, suggesting that fluctuations in eruptive processes affect the electrification processes giving rise to vent discharges. These fluctuations may be variations in eruptive vigor or variations in the type of eruption; however, the data obtained so far do not show a clear relationship between eruption parameters and the intensity or occurrence of vent discharges. Further study is needed to clarify the link between vent discharges and eruptive behavior, such as more detailed lightning observations concurrent with tephra measurements and other measures of eruptive strength. Observations of vent discharges, and volcanic lightning observations in general, are a valuable tool for volcano monitoring, providing a

Índice cronotrópico-metabólico na doença de Chagas

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Rocha Ana Luiza Lunardi

2005-01-01

Full Text Available A insuficiência cronotrópica constitui achado comum entre os pacientes chagásicos. Novas metodologias estão sendo empregadas na avaliação da resposta cronotrópica em vários grupos de pacientes. O índice cronotrópico-metabólico, um desses novos métodos, quantifica a relação entre o aumento da freqüência cardíaca e o consumo máximo de oxigênio (VO2 max durante o teste ergométrico. A resposta normal é linear, com índice em torno de 1,0. Objetivamos avaliar a resposta cronotrópica e em indivíduos saudáveis e pacientes chagásicos com e sem disfunção ventricular esquerda, utilizando-se do índice cronotrópico-metabólico. Foram avaliados 171 pacientes com doença de Chagas sem doenças associadas e 24 controles submetidos a protocolo clínico e ao teste ergométrico máximo. Os chagásicos foram divididos em dois grupos: Ch1= pacientes com fração de ejeção (FE > 39% e Ch 2= FE<40%. A análise e o cálculo do índice cronotrópico-metabólico foram feitos pelo método de Wilkoff. Os pacientes chagásicos apresentaram maior idade e maior prevalência de bloqueio completo de ramo direito, assim como menor VO2 max ao teste ergométrico. Ambos os grupos de chagásicos apresentaram menor inclinação do índice cronotrópico-metabólico (Ch1: 0,91±0,10, Ch2: 0,89±0,08 do que os controles (1,0±0,12, p< 0,001. Pacientes com doença de Chagas com e sem disfunção ventricular esquerda podem apresentar resposta cronotrópica deprimida, manifesta por menor inclinação do índice cronotrópico-metabólico.

Recurrence models of volcanic events: Applications to volcanic risk assessment

International Nuclear Information System (INIS)

Crowe, B.M.; Picard, R.; Valentine, G.; Perry, F.V.

1992-01-01

An assessment of the risk of future volcanism has been conducted for isolation of high-level radioactive waste at the potential Yucca Mountain site in southern Nevada. Risk used in this context refers to a combined assessment of the probability and consequences of future volcanic activity. Past studies established bounds on the probability of magmatic disruption of a repository. These bounds were revised as additional data were gathered from site characterization studies. The probability of direct intersection of a potential repository located in an eight km 2 area of Yucca Mountain by ascending basalt magma was bounded by the range of 10 -8 to 10 -10 yr -1 2 . The consequences of magmatic disruption of a repository were estimated in previous studies to be limited. The exact releases from such an event are dependent on the strike of an intruding basalt dike relative to the repository geometry, the timing of the basaltic event relative to the age of the radioactive waste and the mechanisms of release and dispersal of the waste radionuclides in the accessible environment. The combined low probability of repository disruption and the limited releases associated with this event established the basis for the judgement that the risk of future volcanism was relatively low. It was reasoned that that risk of future volcanism was not likely to result in disqualification of the potential Yucca Mountain site

Volcanic Plume Measurements with UAV (Invited)

Science.gov (United States)

Shinohara, H.; Kaneko, T.; Ohminato, T.

2013-12-01

Volatiles in magmas are the driving force of volcanic eruptions and quantification of volcanic gas flux and composition is important for the volcano monitoring. Recently we developed a portable gas sensor system (Multi-GAS) to quantify the volcanic gas composition by measuring volcanic plumes and obtained volcanic gas compositions of actively degassing volcanoes. As the Multi-GAS measures variation of volcanic gas component concentrations in the pumped air (volcanic plume), we need to bring the apparatus into the volcanic plume. Commonly the observer brings the apparatus to the summit crater by himself but such measurements are not possible under conditions of high risk of volcanic eruption or difficulty to approach the summit due to topography etc. In order to overcome these difficulties, volcanic plume measurements were performed by using manned and unmanned aerial vehicles. The volcanic plume measurements by manned aerial vehicles, however, are also not possible under high risk of eruption. The strict regulation against the modification of the aircraft, such as installing sampling pipes, also causes difficulty due to the high cost. Application of the UAVs for the volcanic plume measurements has a big advantage to avoid these problems. The Multi-GAS consists of IR-CO2 and H2O gas analyzer, SO2-H2O chemical sensors and H2 semiconductor sensor and the total weight ranges 3-6 kg including batteries. The necessary conditions of the UAV for the volcanic plumes measurements with the Multi-GAS are the payloads larger than 3 kg, maximum altitude larger than the plume height and installation of the sampling pipe without contamination of the exhaust gases, as the exhaust gases contain high concentrations of H2, SO2 and CO2. Up to now, three different types of UAVs were applied for the measurements; Kite-plane (Sky Remote) at Miyakejima operated by JMA, Unmanned airplane (Air Photo Service) at Shinomoedake, Kirishima volcano, and Unmanned helicopter (Yamaha) at Sakurajima

The Massive Compound Cofre de Perote Shield Volcano: a Volcanological Oddity in the Eastern Mexican Volcanic Belt

Science.gov (United States)

Siebert, L.; Carrasco-Nunez, G.; Diaz-Castellon, R.; Rodriguez, J. L.

2007-12-01

Cofre de Perote volcano anchors the northern end of the easternmost of several volcanic chains orthogonal to the E-W trend of the Mexican Volcanic Belt (MVB). Its structure, geochemistry, and volcanic history diverge significantly from that of the large dominantly andesitic stratovolcanoes that have been the major focus of research efforts in the MVB. Andesitic-trachyandesitic to dacitic-trachydacitic effusive activity has predominated at Cofre de Perote, forming a massive low-angle compound shield volcano that dwarfs the more typical smaller shield volcanoes of the central and western MVB. The 4282-m-high volcano overlooking Xalapa, the capital city of the State of Veracruz, has a diameter of about 30 km and rises more than 3000 m above the coastal plain to the east. Repeated edifice collapse has left massive horseshoe-shaped scarps that truncate the eastern side of the edifice. Five major evolutionary stages characterize the growth of this compound volcano: 1) emplacement of a multiple-vent dome complex forming the basal structure of Cofre de Perote around 1.9-1.3 Ma; 2) construction of the basal part of the compound shield volcano from at least two main upper-edifice vents at about 400 ka; 3) effusion of the summit dome-like lavas through multiple vents at ca. 240 ka; 4) eruption of a large number of geochemically diverse, alkaline and calc-alkaline Pleistocene-to-Holocene monogenetic cones (likely related to regional volcanism) through the flanks of the Cofre de Perote edifice; 5) late-stage, large-volume edifice collapse on at least two occasions (ca. 40 ka and ca. 10 ka), producing long-runout debris avalanches that traveled to the east. An undated tephra layer from Cofre de Perote overlies deposits likely of the youngest collapse. Cofre de Perote is one of several volcanoes in the roughly N-S-trending chain that has undergone major edifice collapse. As with Citlaltepetl (Pico de Orizaba) and Las Cumbres volcanoes, Cofre de Perote was constructed at the

Spatial structure and associations in Pinus canariensis population at the treeline, Pico del Teide, Tenerife, Canary Islands

Czech Academy of Sciences Publication Activity Database

Šrůtek, Miroslav; Doležal, J.; Hara, T.

2002-01-01

Roč. 34, č. 2 (2002), s. 201-210 ISSN 1523-0430 R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6005908 Keywords : Pinus canariensis * Canary Islands Subject RIV: EF - Botanics Impact factor: 0.964, year: 2002

Spatial structure and associations in Pinus canariensis population at the treeline, Pico del Teide, Tenerife, Canary Islands

Czech Academy of Sciences Publication Activity Database

Šrůtek, Miroslav; Doležal, J.; Hara, T.

2002-01-01

Roč. 34, č. 2 (2002), s. 201-210 ISSN 1523-0430 R&D Projects: GA ČR(CZ) GA206/00/1445; GA AV ČR(CZ) KSK6005114 Institutional research plan: CEZ:AV0Z6005908 Keywords : Pinus canariensis * Canary Islands Subject RIV: EF - Botanics Impact factor: 0.964, year: 2002

Conceptual model of volcanism and volcanic hazards of the region of Ararat valley, Armenia

Science.gov (United States)

Meliksetian, Khachatur; Connor, Charles; Savov, Ivan; Connor, Laura; Navasardyan, Gevorg; Manucharyan, Davit; Ghukasyan, Yura; Gevorgyan, Hripsime

2015-04-01

Armenia and the adjacent volcanically active regions in Iran, Turkey and Georgia are located in the collision zone between the Arabian and Eurasian lithospheric plates. The majority of studies of regional collision related volcanism use the model proposed by Keskin, (2003) where volcanism is driven by Neo-Tethyan slab break-off. In Armenia, >500 Quaternary-Holocene volcanoes from the Gegham, Vardenis and Syunik volcanic fields are hosted within pull-apart structures formed by active faults and their segments (Karakhanyan et al., 2002), while tectonic position of the large in volume basalt-dacite Aragats volcano and periphery volcanic plateaus is different and its position away from major fault lines necessitates more complex volcano-tectonic setup. Our detailed volcanological, petrological and geochemical studies provide insight into the nature of such volcanic activity in the region of Ararat Valley. Most magmas, such as those erupted in Armenia are volatile-poor and erupt fairly hot. Here we report newly discovered tephra sequences in Ararat valley, that were erupted from historically active Ararat stratovolcano and provide evidence for explosive eruption of young, mid K2O calc-alkaline and volatile-rich (>4.6 wt% H2O; amph-bearing) magmas. Such young eruptions, in addition to the ignimbrite and lava flow hazards from Gegham and Aragats, present a threat to the >1.4 million people (~ ½ of the population of Armenia). We will report numerical simulations of potential volcanic hazards for the region of Ararat valley near Yerevan that will include including tephra fallout, lava flows and opening of new vents. Connor et al. (2012) J. Applied Volcanology 1:3, 1-19; Karakhanian et al. (2002), JVGR, 113, 319-344; Keskin, M. (2003) Geophys. Res. Lett. 30, 24, 8046.

Experimental model for endometriosis. Comparative histological study between the ectopic and eutopic endometrium Modelo experimental de endometriose: estudo histológico comparativo entre o endométrio estópico e o eutópico

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Cézar Alencar de Lima Rezende

1997-12-01

Full Text Available Thyrty-six rats werw implanted with endometrial squares (2 X 2mm to the left parietal peritoneum and the right uterine horn was tied. The rats were mated for 20 days and then sacrificed. Topic and ectopic endometrial histological pattern were compared. There was a correlation between the histological pattern of the autografted endometrium and the eutopic endometrium im most rats, pregnant or not. This suggests that both responded in a similar way to the same endocrine stimuli. The experimental model for endometriosis admiting the histological correlation between the uterine endometrium and the ectopic is factible and it is easy to be repetead.Trinta e seis ratas foram submetidas a implante cirúrgico de retalho endometrial quadrangular (2 x 2mm no peritônio parietal esquerdo e ligadura do corno uterino direito. As ratas foram acasaladas por 20 dias e logo após sacrificadas. Foram comparados o padrão histológico do endométrio eutópico e do ectópico.Houve correspondência entre o padrão histológico do endométrio auto-transplantado e o endométrio eutópico na maioria das ratas, prenhes ou não, sugerindo que ambos responderam de forma semelhante aos mesmo estímulos endócrinos. O modelo experimental de endometriose na rata, permitindo a correlação histológica entre o endométrio uterino e o ectópico, é viável e de fácil repetição.

Closer look at lunar volcanism

International Nuclear Information System (INIS)

Vaniman, D.T.; Heiken, G.; Taylor, G.J.

1984-01-01

Although the American Apollo and Soviet Luna missions concentrated on mare basalt samples, major questions remain about lunar volcanism. Lunar field work will be indispensable for resolving the scientific questions about ages, compositions, and eruption processes of lunar volcanism. From a utilitarian standpoint, a better knowledge of lunar volcanism will also yield profitable returns in lunar base construction (e.g., exploitation of rille or lava-tube structures) and in access to materials such as volatile elements, pure glass, or ilmenite for lunar industry

Volcanic alert system (VAS) developed during the 2011-2014 El Hierro (Canary Islands) volcanic process

Science.gov (United States)

García, Alicia; Berrocoso, Manuel; Marrero, José M.; Fernández-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Ortiz, Ramón

2014-06-01

The 2011 volcanic unrest at El Hierro Island illustrated the need for a Volcanic Alert System (VAS) specifically designed for the management of volcanic crises developing after long repose periods. The VAS comprises the monitoring network, the software tools for analysis of the monitoring parameters, the Volcanic Activity Level (VAL) management, and the assessment of hazard. The VAS presented here focuses on phenomena related to moderate eruptions, and on potentially destructive volcano-tectonic earthquakes and landslides. We introduce a set of new data analysis tools, aimed to detect data trend changes, as well as spurious signals related to instrumental failure. When data-trend changes and/or malfunctions are detected, a watchdog is triggered, issuing a watch-out warning (WOW) to the Monitoring Scientific Team (MST). The changes in data patterns are then translated by the MST into a VAL that is easy to use and understand by scientists, technicians, and decision-makers. Although the VAS was designed specifically for the unrest episodes at El Hierro, the methodologies may prove useful at other volcanic systems.

Pico hydro power for rural electrification in developing countries

International Nuclear Information System (INIS)

Maher, P.; Smith, N.P.A.; Williams, A.A.

1998-01-01

Pico hydro power is a renewable energy system which has the potential to provide millions of rural people world-wide with a cheap, sustainable source of electricity. The development of new, cost-reducing approaches, including local manufacture and implementation in developing countries, has increased the accessibility of this technology to large numbers of people. The new approaches are investigated and some of the present constraints to wider adoption of this technology are analysed. (Author)

Utilização de fitoterápicos por idosos: resultados de um inquérito domiciliar em Belo Horizonte (MG, Brasil

Directory of Open Access Journals (Sweden)

Lucianno D. P. Marliére

Full Text Available Os fitoterápicos constituem uma modalidade de terapia complementar ou alternativa diante das necessidades de saúde e seu uso tem sido crescente na população idosa de diversos países. Entretanto, apresentam interações medicamentosas e reações adversas importantes e sua utilização não deve ser indiscriminada. Este estudo objetivou caracterizar o perfil de utilização de fitoterápicos por aposentados e pensionistas do INSS, com 60 anos e mais, residentes em Belo Horizonte, MG. A partir do cadastro do INSS, selecionou-se uma amostra aleatória de 881 idosos para entrevista. Investigou-se a prevalência de uso de fitoterápicos e interações medicamentosas potenciais. Um total de 667 (80,3% dos selecionados foi entrevistado. Setenta e um participantes (10,6% utilizaram fitoterápicos nos últimos 15 dias, principalmente aqueles preparados a partir de extratos de ginkgo (41,8%, aesculus (12,3% e isoflavonas de soja (8,2%. Mais de 60% dos fitoterápicos foram adquiridos em farmácias de manipulação. Aproximadamente 45% dos usuários de fitoterápicos estavam expostos a pelo menos uma interação medicamentosa potencial entre eles e medicamentos sintéticos, tais como entre ginkgo e diuréticos tiazídicos (14 e antiagregante plaquetário/anticoagulantes (8. São necessárias estratégias de orientação para o uso racional de fitoterápicos entre idosos, mais vulneráveis aos prejuízos decorrentes da utilização inadequada desses.

Lidar sounding of volcanic plumes

Science.gov (United States)

Fiorani, Luca; Aiuppa, Alessandro; Angelini, Federico; Borelli, Rodolfo; Del Franco, Mario; Murra, Daniele; Pistilli, Marco; Puiu, Adriana; Santoro, Simone

2013-10-01

Accurate knowledge of gas composition in volcanic plumes has high scientific and societal value. On the one hand, it gives information on the geophysical processes taking place inside volcanos; on the other hand, it provides alert on possible eruptions. For this reasons, it has been suggested to monitor volcanic plumes by lidar. In particular, one of the aims of the FP7 ERC project BRIDGE is the measurement of CO2 concentration in volcanic gases by differential absorption lidar. This is a very challenging task due to the harsh environment, the narrowness and weakness of the CO2 absorption lines and the difficulty to procure a suitable laser source. This paper, after a review on remote sensing of volcanic plumes, reports on the current progress of the lidar system.

Gas measurements from the Costa Rica-Nicaragua volcanic segment suggest possible along-arc variations in volcanic gas chemistry

Science.gov (United States)

Aiuppa, A.; Robidoux, P.; Tamburello, G.; Conde, V.; Galle, B.; Avard, G.; Bagnato, E.; De Moor, J. M.; Martínez, M.; Muñóz, A.

2014-12-01

Obtaining accurate estimates of the CO2 output from arc volcanism requires a precise understanding of the potential along-arc variations in volcanic gas chemistry, and ultimately of the magmatic gas signature of each individual arc segment. In an attempt to more fully constrain the magmatic gas signature of the Central America Volcanic Arc (CAVA), we present here the results of a volcanic gas survey performed during March and April 2013 at five degassing volcanoes within the Costa Rica-Nicaragua volcanic segment (CNVS). Observations of the volcanic gas plume made with a multicomponent gas analyzer system (Multi-GAS) have allowed characterization of the CO2/SO2-ratio signature of the plumes at Poás (0.30±0.06, mean ± SD), Rincón de la Vieja (27.0±15.3), and Turrialba (2.2±0.8) in Costa Rica, and at Telica (3.0±0.9) and San Cristóbal (4.2±1.3) in Nicaragua (all ratios on molar basis). By scaling these plume compositions to simultaneously measured SO2 fluxes, we estimate that the CO2 outputs at CNVS volcanoes range from low (25.5±11.0 tons/day at Poás) to moderate (918 to 1270 tons/day at Turrialba). These results add a new information to the still fragmentary volcanic CO2 output data set, and allow estimating the total CO2 output from the CNVS at 2835±1364 tons/day. Our novel results, with previously available information about gas emissions in Central America, are suggestive of distinct volcanic gas CO2/ST (= SO2 + H2S)-ratio signature for magmatic volatiles in Nicaragua (∼3) relative to Costa Rica (∼0.5-1.0). We also provide additional evidence for the earlier theory relating the CO2-richer signature of Nicaragua volcanism to increased contributions from slab-derived fluids, relative to more-MORB-like volcanism in Costa Rica. The sizeable along-arc variations in magmatic gas chemistry that the present study has suggested indicate that additional gas observations are urgently needed to more-precisely confine the volcanic CO2 from the CAVA, and from

Tratamento Videolaparoscópico de Endometriomas Ovarianos

Directory of Open Access Journals (Sweden)

Lopez Adriana C.S.

2000-01-01

Full Text Available Objetivo: avaliar os resultados do tratamento videolaparoscópico de 32 pacientes com endometrioma ovariano. Métodos: estudo retrospectivo que incluiu trinta e duas pacientes encaminhadas ao setor de Endoscopia Ginecológica do Serviço de Ginecologia e Obstetrícia do Hospital do Servidor Público Estadual "Francisco Morato de Oliveira" - São Paulo, as quais tinham diagnóstico clínico e ultra-sonográfico de endometrioma ovariano e foram tratadas por videolaparoscopia. Onze pacientes com endometriomas com diâmetro menor que 3 cm foram submetidas à drenagem do endometrioma e exérese da cápsula na primeira laparoscopia. Vinte e uma pacientes com endometriomas com diâmetros maior que 3 cm foram submetidas à drenagem do endometrioma e lavagem do cisto na primeira laparoscopia. A seguir, utilizaram análogo do GnRH por quatro meses (1 ampola mensal e então foram submetidas à segunda laparoscopia para retirada da cápsula do endometrioma. O exame histopatológico do material obtido na cirurgia foi realizado em todos os casos. Avaliou-se o resultado imediato do procedimento e a freqüência de recidivas. Resultados: não se registraram intercorrências cirúrgicas ou complicações pós-operatórias. Ocorreram três recidivas em um período de seis a doze meses, todas no grupo de 21 pacientes com endometriomas com o diâmetro maior que 3 cm. Conclusão: o tratamento videolaparoscópico dos endometriomas ovarianos com retirada da cápsula apresenta bons resultados e baixo índice de recidiva.

Structural control of monogenetic volcanism in the Garrotxa volcanic field (Northeastern Spain) from gravity and self-potential measurements

Science.gov (United States)

Barde-Cabusson, S.; Gottsmann, J.; Martí, J.; Bolós, X.; Camacho, A. G.; Geyer, A.; Planagumà, Ll.; Ronchin, E.; Sánchez, A.

2014-01-01

We report new geophysical observations on the distribution of subsurface structures associated with monogenetic volcanism in the Garrotxa volcanic field (Northern Spain). As part of the Catalan Volcanic Zone, this Quaternary volcanic field is associated with the European rifts system. It contains the most recent and best preserved volcanic edifices of the Catalan Volcanic Zone with 38 monogenetic volcanoes identified in the Garrotxa Natural Park. We conducted new gravimetric and self-potential surveys to enhance our understanding of the relationship between the local geology and the spatial distribution of the monogenetic volcanoes. The main finding of this study is that the central part of the volcanic field is dominated by a broad negative Bouguer anomaly of around -0.5 mGal, within which a series of gravity minima are found with amplitudes of up to -2.3 mGal. Inverse modelling of the Bouguer data suggests that surficial low-density material dominates the volcanic field, most likely associated with effusive and explosive surface deposits. In contrast, an arcuate cluster of gravity minima to the NW of the Croscat volcano, the youngest volcano of this zone, is modelled by vertically extended low-density bodies, which we interpret as a complex ensemble of fault damage zones and the roots of young scoria cones. A ground-water infiltration zone identified by a self-potential anomaly is associated with a steep horizontal Bouguer gravity gradient and interpreted as a fault zone and/or magmatic fissure, which fed the most recent volcanic activity in the Garrotxa. Gravimetric and self-potential data are well correlated and indicate a control on the locations of scoria cones by NNE-SSW and NNW-SSE striking tectonic features, which intersect the main structural boundaries of the study area to the north and south. Our interpretation of the data is that faults facilitated magma ascent to the surface. Our findings have major implications for understanding the relationship

Volcanic Hazards in Site Evaluation for Nuclear Installations

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-10-15

This publication provides comprehensive and updated guidance for site evaluation in relation to volcanic hazards. It includes recommendations on assessing the volcanic hazards at a nuclear installation site, in order to identify and characterize, in a comprehensive manner, all potentially hazardous phenomena that may be associated with future volcanic events. It describes how some of these volcanic phenomena may affect the acceptability of the selected site, resulting in exclusion of a site or determining the corresponding design basis parameters for the installation. This Safety Guide is applicable to both existing and new sites, and a graded approach is recommended to cater for all types of nuclear installations. Contents: 1. Introduction; 2. Overview of volcanic hazard assessment; 3. General recommendations; 4. Necessary information and investigations (database); 5. Screening of volcanic hazards; 6. Site specific volcanic hazard assessment; 7. Nuclear installations other than nuclear power plants; 8. Monitoring and preparation for response; 9. Management system for volcanic hazard assessment; Annex I: Volcanic hazard scenarios; Annex II: Worldwide sources of information.

Volcanic ash in ancient Maya ceramics of the limestone lowlands: implications for prehistoric volcanic activity in the Guatemala highlands

Science.gov (United States)

Ford, Anabel; Rose, William I.

1995-07-01

In the spirit of collaborative research, Glicken and Ford embarked on the problem of identifying the source of volcanic ash used as temper in prehistoric Maya ceramics. Verification of the presence of glass shards and associated volcanic mineralogy in thin sections of Maya ceramics was straightforward and pointed to the Guatemala Highland volcanic chain. Considering seasonal wind rose patterns, target volcanoes include those from the area west of and including Guatemala City. Joint field research conducted in 1983 by Glicken and Ford in the limestone lowlands of Belize and neighboring Guatemala, 300 km north of the volcanic zone and 150 km from the nearest identified ash deposits, was unsuccessful in discovering local volcanic ash deposits. The abundance of the ash in common Maya ceramic vessels coupled with the difficulties of long-distance procurement without draft animals lead Glicken to suggest that ashfall into the lowlands would most parsimoniously explain prehistoric procurement; it literally dropped into their hands. A major archaeological problem with this explanation is that the use of volcanic ash occurring over several centuries of the Late Classic Period (ca. 600-900 AD). To accept the ashfall hypothesis for ancient Maya volcanic ash procurement, one would have to demonstrate a long span of consistent volcanic activity in the Guatemala Highlands for the last half of the first millennium AD. Should this be documented through careful petrographic, microprobe and tephrachronological studies, a number of related archaeological phenomena would be explained. In addition, the proposed model of volcanic activity has implications for understanding volcanism and potential volcanic hazards in Central America over a significantly longer time span than the historic period. These avenues are explored and a call for further collaborative research of this interdisciplinary problem is extended in this paper.

Incident Wave Climate at the OWC Pico Plant

DEFF Research Database (Denmark)

Le Crom, I.; Cabrera Bermejo, H.; Pecher, Arthur

2011-01-01

The aim of the study is to retrieve the incident wave information that coincides with former Pico plant operation periods. The recent implementation of a directional pressure sensor for wave measurement as well as the recovery of the data gathered by a directional wave rider buoy allowed embarkin...... on the validation of two different models by using both wave measurements: a model for wave propagation (SWAN) and an Artificial Neural Network (ANN). This paper, as a first step of a comprehensive study, leads to several recommendations to improve both methodologies in future works....

Geophysical expression of caldera related volcanism, structures and mineralization in the McDermitt volcanic field

Science.gov (United States)

Rytuba, J. J.; Blakely, R. J.; Moring, B.; Miller, R.

2013-12-01

The High Rock, Lake Owyhee, and McDermitt volcanic fields, consisting of regionally extensive ash flow tuffs and associated calderas, developed in NW Nevada and SE Oregon following eruption of the ca. 16.7 Ma Steens flood basalt. The first ash flow, the Tuff of Oregon Canyon, erupted from the McDermitt volcanic field at 16.5Ma. It is chemically zoned from peralkaline rhyolite to dacite with trace element ratios that distinguish it from other ash flow tuffs. The source caldera, based on tuff distribution, thickness, and size of lithic fragments, is in the area in which the McDermitt caldera (16.3 Ma) subsequently formed. Gravity and magnetic anomalies are associated with some but not all of the calderas. The White Horse caldera (15.6 Ma), the youngest caldera in the McDermitt volcanic field has the best geophysical expression, with both aeromagnetic and gravity lows coinciding with the caldera. Detailed aeromagnetic and gravity surveys of the McDermitt caldera, combined with geology and radiometric surveys, provides insight into the complexities of caldera collapse, resurgence, post collapse volcanism, and hydrothermal mineralization. The McDermitt caldera is among the most mineralized calderas in the world, whereas other calderas in these three Mid Miocene volcanic fields do not contain important hydrothermal ore deposits, despite having similar age and chemistry. The McDermitt caldera is host to Hg, U, and Li deposits and potentially significant resources of Ga, Sb, and REE. The geophysical data indicate that post-caldera collapse intrusions were important in formation of the hydrothermal systems. An aeromagnetic low along the E caldera margin reflects an intrusion at a depth of 2 km associated with the near-surface McDermitt-hot-spring-type Hg-Sb deposit, and the deeper level, high-sulfidation Ga-REE occurrence. The Li deposits on the W side of the caldera are associated with a series of low amplitude, small diameter aeromagnetic anomalies that form a continuous

Modelling ground deformation patterns associated with volcanic processes at the Okataina Volcanic Centre

Science.gov (United States)

Holden, L.; Cas, R.; Fournier, N.; Ailleres, L.

2017-09-01

The Okataina Volcanic Centre (OVC) is one of two large active rhyolite centres in the modern Taupo Volcanic Zone (TVZ) in the North Island of New Zealand. It is located in a complex section of the Taupo rift, a tectonically active section of the TVZ. The most recent volcanic unrest at the OVC includes the 1315 CE Kaharoa and 1886 Tarawera eruptions. Current monitoring activity at the OVC includes the use of continuous GPS receivers (cGPS), lake levelling and seismographs. The ground deformation patterns preceding volcanic activity the OVC are poorly constrained and restricted to predictions from basic modelling and comparison to other volcanoes worldwide. A better understanding of the deformation patterns preceding renewed volcanic activity is essential to determine if observed deformation is related to volcanic, tectonic or hydrothermal processes. Such an understanding also means that the ability of the present day cGPS network to detect these deformation patterns can also be assessed. The research presented here uses the finite element (FE) modelling technique to investigate ground deformation patterns associated with magma accumulation and diking processes at the OVC in greater detail. A number of FE models are produced and tested using Pylith software and incorporate characteristics of the 1315 CE Kaharoa and 1886 Tarawera eruptions, summarised from the existing body of research literature. The influence of a simple ring fault structure at the OVC on the modelled deformation is evaluated. The ability of the present-day continuous GPS (cGPS) GeoNet monitoring network to detect or observe the modelled deformation is also considered. The results show the modelled horizontal and vertical displacement fields have a number of key features, which include prominent lobe based regions extending northwest and southeast of the OVC. The results also show that the ring fault structure increases the magnitude of the displacements inside the caldera, in particular in the

Accelerating customer integration into innovation processes using Pico-Jobs

OpenAIRE

Blohm, Ivo;Fähling, Jens;Leimeister, Jan Marco;Krcmar, Helmut;Fischer, Jan

2014-01-01

Crowdsourcing marketplaces emerged in the internet and enable the integration of customers in various tasks along the innovation process. Marketplaces such as Amazon?s Mechanical Turk install a member base for third parties, where they can offer small, highly structured paid tasks which can hardly be solved automatically with ICT which we call Pico Jobs. In this paper a new method for systematically utilizing the creative potential of the users of these marketplaces for new product developmen...

Volcanism and associated hazards: the Andean perspective

Science.gov (United States)

Tilling, R. I.

2009-12-01

Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (Colombia) killed about 25 000 people - the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant

Climatic fluctuations as a significant contributing factor for volcanic collapses. Evidence from Mexico during the Late Pleistocene

Science.gov (United States)

Capra, L.; Bernal-Uruchurtu, J. P.; Carrasco, G.

2013-05-01

Climate oscillations have significantly contributed to the planet's evolution, including volcanic activity. Major glaciations have been considered not only as a triggering mechanism for large magmatic eruptions but also inducing volcano instability. Generally, volcano instability can be inferred from detailed volcanological and structural studies of a volcano and its associated depositional sequence, but the triggering mechanism has been always difficult to infer. In this paper, we present evidence of how climatic variations during the Late Pleistocene could have forced sector collapses of the main Mexican stratovolcanoes and enhanced the mobility of associated massive flows inducing the transformation of debris avalanche into debris flows. In particular, the climatic record based on atmospheric moisture content from robustly dated lake record from Guatemala and a U/Th dated speleothem from New Mexico are used here as indicators of summer and winter precipitation. Depositional sequences associated with Late Pleistocene sector collapses of Volcan de Colima, Nevado de Toluca, Citlaltepetl (Pico de Orizaba) and Cofre de Perote volcanoes are here analyzed. Comparing the timing of the event with the climatic record, a combination of summer and/or winter pluvial conditions could have forced and triggered the failure of already unstable volcanoes, even during glacier advances (as for the Citlaltepetl event). Independently of the main cause of the volcano instability (magmatic or tectonic) it is important to highlight that the climatic factor played an important role in enhancing the volcano instability and promoted the lateral transformation of debris avalanches, which under dry conditions would have affected more limited areas.

Performance Assessment of the Pico OWC Power Plant Following the Equimar Methodology

DEFF Research Database (Denmark)

Pecher, Arthur; Crom, I. Le; Kofoed, Jens Peter

2011-01-01

This paper presents the power performance of the Oscillating Water Column (OWC) wave energy converter installed on the Island of Pico. The performance assessment of the device is based on real performance data gathered over the last years during normal operation. In addition to the estimation...

Pitiose eqüina no Pantanal brasileiro: aspectos clínico-patológicos de casos típicos e atípicos Equine pythiosis in the Brazilian Pantanal region: clinical and pathological findings of typical and atypical cases

Directory of Open Access Journals (Sweden)

Adriana B. Monteiro Leal

2001-12-01

Full Text Available A pitiose eqüina é doença endêmica no Pantanal Brasileiro e causa prejuízos significativos a eqüinocultura. Neste trabalho são relatados 16 casos de pitiose subcutânea em eqüinos no Pantanal Sul-Matogrossense, que foram divididos em onze casos típicos e cinco casos atípicos, de acordo com o quadro clínico e o tempo de duração das lesões. O diagnóstico foi confirmado pela detecção de anticorpos específicos pelo teste ELISA, isolamento do agente e histopato-lógico. A duração da doença variou entre 1 e 6 meses nos casos típicos e superior a 12 meses nos casos atípicos. As lesões dos casos típicos caracterizavam-se por granulomas subcutâneos, ulcerados, com abundante secreção serossangui-nolenta e prurido. Nos casos atípicos foram observadas lesões subcutâneas caracterizadas por grandes massas "tumorais" circunscritas, recobertas por pele escura, sem ulcerações e com pouca secreção. Os animais estavam em bom estado nutricional e as lesões apresentavam-se de aspecto organizado, às vezes pedunculadas. Histologicamente, foi observado tecido de granulação com muitos eosinófilos nos casos típicos, enquanto os atípicos, se caracterizaram por hiperplasia pseudo-epiteliomatosa da epiderme e infiltrado eosinofílico. As características clínicas e histopato-lógicas completas das duas formas clínicas e os possíveis fatores responsáveis pelas diferenças entre as duas formas são apresentados e discutidos.Equine pythiosis is an endemic disease of horses and causes significant economic losses to equine breeding in the Brazilian Pantanal. This article describes 16 cases of subcutaneous pythiosis in horses from that region. The clinical cases were divided in typical (11 and atypical (5, according to the clinical features and duration of the disease. The clinical diagnosis was confirmed by detection of specific antibodies by ELISA, isolation of the agent and histopathology. The duration of the disease varied from 1

Global volcanic emissions: budgets, plume chemistry and impacts

Science.gov (United States)

Mather, T. A.

2012-12-01

Over the past few decades our understanding of global volcanic degassing budgets, plume chemistry and the impacts of volcanic emissions on our atmosphere and environment has been revolutionized. Global volcanic emissions budgets are needed if we are to make effective use of regional and global atmospheric models in order to understand the consequences of volcanic degassing on global environmental evolution. Traditionally volcanic SO2 budgets have been the best constrained but recent efforts have seen improvements in the quantification of the budgets of other environmentally important chemical species such as CO2, the halogens (including Br and I) and trace metals (including measurements relevant to trace metal atmospheric lifetimes and bioavailability). Recent measurements of reactive trace gas species in volcanic plumes have offered intriguing hints at the chemistry occurring in the hot environment at volcanic vents and during electrical discharges in ash-rich volcanic plumes. These reactive trace species have important consequences for gas plume chemistry and impacts, for example, in terms of the global fixed nitrogen budget, volcanically induced ozone destruction and particle fluxes to the atmosphere. Volcanically initiated atmospheric chemistry was likely to have been particularly important before biological (and latterly anthropogenic) processes started to dominate many geochemical cycles, with important consequences in terms of the evolution of the nitrogen cycle and the role of particles in modulating the Earth's climate. There are still many challenges and open questions to be addressed in this fascinating area of science.

COMPORTAMIENTO PRODUCTIVO DE NOVILLOS PASTOREANDO EN TRÓPICO DE ALTU RA CON Y SIN SUPLEMENTACIÓN ENERGÉTICA

Directory of Open Access Journals (Sweden)

C. P. Sossa

2015-01-01

Full Text Available En Colombia, la producción de carne bovina tradicionalmente se realiza en el trópico bajo, mientras que en el trópico de altura, los sistemas ganaderos predominantes son de lechería especializada. Las gramíneas de trópico alto son de mayor valor nutricional que las de trópico bajo, aunque pueden presentar un exceso de proteína, por lo cual una estrategia de suplementación debe basarse en la inclusión de materias primas energéticas. Al analizar la oferta de nutrientes en el pasto kikuyo (Pennisetum clandestinum se observan altos contenidos de proteína (20.6% y baja disponibilidad de energía (2.31 Mcal EM/ kg. Así, el presente estudio se realizó con el propósito de evaluar la producción de carne bovina en condiciones de trópico de altura (Santa Rosa de Osos, Antioquia. Durante 122 días se evaluó el crecimiento de 18 novillos de diversos cruces, que pastoreaban en dos grupos en praderas de kikuyo hasta alcanzar el peso de beneficio (420 kg. El primer grupo (peso inicial 316±370 kg recibió 0.55 kg/día de un suplemento energético a base de maíz, melaza y sebo (51%, 12% y 37%, respectivamente, mientras el segundo grupo (peso inicial 322,8±27.8 kg se encontraba sólo en pastoreo. Los animales suplementados (CS pastoreaban en 2.5 ha y los no suplementados (SS en 3.2 ha. Hubo una ganancia total de 78.8 y 73.3 kg de peso/novillo durante todo el período, equivalentes a ganar 646 y 601 gr/animal/día y a producir 848.5 y 617.1 kg de carne/ha/año en el sistema CS y SS, respectivamente. Cebar novillos en trópico de altura puede ser una actividad productiva exitosa, pero es necesario identificar, tanto el nivel de inclusión, como la fuente energética adecuada para mejorar la relación energía:proteína en la dieta de animales pastoreando P. clandestinum.

Computer-Presented Organizational/Memory Aids as Instruction for Solving Pico-Fomi Problems.

Science.gov (United States)

Steinberg, Esther R.; And Others

1985-01-01

Describes investigation of effectiveness of computer-presented organizational/memory aids (matrix and verbal charts controlled by computer or learner) as instructional technique for solving Pico-Fomi problems, and the acquisition of deductive inference rules when such aids are present. Results indicate chart use control should be adapted to…

Holocene volcanic geology, volcanic hazard, and risk on Taveuni, Fiji

International Nuclear Information System (INIS)

Cronin, S.J.; Neall, V.E.

2001-01-01

The Holocene volcanic geology of Taveuni has been mapped in order to produce a volcanic hazard and risk assessment for the island. Taveuni is the third-largest island of the Fiji group and home to 14,500 people. At least cubic km 2.7 of olivine-alkali-basalt magma was erupted from over 100 events throughout the Holocene. Vents are concentrated along a northeast-striking rift zone that is parallel to other regional structural trends. There is an overall trend of younging southward along the rift. Holocene lavas and tephras are grouped within six newly defined eruptive periods, established on a basis of radiocarbon dating. Within these periods, 14 tephra layers, useful as local marker horizons, are recognised. At least 58% of Holocene eruptions produced lava flows, while almost all produced some tephra. Individual eruption event volumes ranged between 0.001 and cubic km 0.20 (dense rock equivalent). Many eruptions involved at least some phases of phreatic and/or phreato-magmatic activity, although dominant hydrovolcanic activity was limited to only a few events. A volcanic hazard map is presented, based on the Holocene geology map and statistical analyses of eruption recurrence. The highest levels of ground-based and near-vent hazards are concentrated along the southern portion of the island's rift axis, with the paths of initial lava flows predicted from present topography. Tephra fall hazards are based on eruption parameters interpreted from mapped Holocene tephra layers. Hawaiian explosive-style eruptions appear to be a dominant eruptive process, with prevailing low-level (<3 km) southeasterly winds dispersing most tephra to the northwestern quadrant. Vulnerable elements (population centres, infrastructure, and economy) on Taveuni have been considered in deriving a volcanic risk assessment for the island. A number of infrastructural and subdivision developments are either under way or planned for the island, driven by its highly fertile soils and availability of

Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

Directory of Open Access Journals (Sweden)

Langgeng Wahyu Santosa

2013-07-01

Full Text Available Geomorphologial approach can be used as the basic for identifying and analyzing the natural resources potentials, especially in volcanic landscape. Based on its geomorphology, Merapi volcanic landscape can be divided into 5 morphological units, i.e.: volcanic cone, volcanic slope, volcanic foot, volcanic foot plain, and fluvio-volcanic plain. Each of these morphological units has specific characteristic and natural resources potential. Based on the condition of geomorphology, the regional zoning can be compiled to support the land use planning and to maintain the conservation of environmental function in the Merapi Volcanic area.

Perfil fenotípico e genotípico de Staphylococcus aureus isolados de estudantes de enfermagem, 2008 Perfil fenotípico y genotípico del Staphylococcus aureus aislados de estudiantes de enfermería, 2008 Phenotypic and genotypic profile of Staphylococcus aureus isolated in nursing students, 2008

Directory of Open Access Journals (Sweden)

Suelen Teixeira Faria

2011-01-01

Full Text Available OBJETIVO: Verificar a prevalência de carreamento nasal, perfil fenotípico e genotípico de S. aureus isolados de estudantes de enfermagem. MÉTODOS: Estudo transversal, com população composta por 101 alunos, cursando as três primeiras séries do curso de graduação em Enfermagem no ano de 2008. S. aureus foi isolado de material biológico obtido dos vestíbulos nasais através de swab. A susceptibilidade à oxacilina e vancomicina foi determinada pelo teste de concentração inibitória mínima. A presença do gene MecA foi determinada pelo teste de reação em cadeia da polimerase. RESULTADOS: Verificou-se 90,1% de positividade para S. aureus. A frequência de resistência à oxacilina foi de 9,8% e todas as amostras foram sensíveis à vancomicina. A oito amostras resistentes À oxacilina apresentaram o gene MecA. CONCLUSÃO: A prevalência foi elevada. A resistência à oxacilna foi expressiva e todas as amostras foram sensíveis à vancomicina. As amostras resistentes à oxacilina carreavam o gene MecA.OBJETIVO: Verificar la prevalencia de transporte nasal, perfil fenotípico y genotípico de S. aureus aislados de estudiantes de enfermería. MÉTODOS: Estudio transversal, con población compuesta por 101 alumnos, cursando las tres primeras series del Pregrado en Enfermería en el año 2008. El S. aureus fue aislado del material biológico obtenido de los vestíbulos nasales a través de swab. La susceptibilidad a la oxacilina y vancomicina fue determinada por el test de concentración inhibitoria mínima. La presencia del gen MecA fue determinada por el test de reacción en cadena de la polimerasa. RESULTADOS: Se verificó el 90,1% de positividad para el S. aureus. La frecuencia de resistencia a la oxacilina fue de 9,8% y todas las muestras fueron sensibles a la vancomicina. Las ocho muestras resistentes a la oxacilina presentaron el gen MecA. CONCLUSION: La prevalencia fue elevada. La resistencia a la oxacilina fue expresiva y todas

Diffuse CO2 fluxes from Santiago and Congro volcanic lakes (São Miguel, Azores archipelago)

Science.gov (United States)

Andrade, César; Cruz, José; Viveiros, Fátima; Branco, Rafael

2017-04-01

Diffuse CO2 degassing occurring in Santiago and Congro lakes, both located in depressions associated to maars from São Miguel Island (Azores, Portugal), was studied through detailed flux measurements. Four sampling campaigns were developed between 2013 and 2016 in each water body, split by the cold and wet seasons. São Miguel has an area of 744.6 km2, being the largest island of the archipelago. The geology of the island is dominated by three quiescent central volcanoes (Sete Cidades, Fogo and Furnas), linked by volcanic fissural zones (Picos and Congro Fissural Volcanic systems). The oldest volcanic systems of the island are located in its eastern part (Povoação-Nordeste). Santiago lake, with a surface area of 0.26 km2 and a depth of 30.5 m, is located inside a maar crater in the Sete Cidades volcano at an altitude of 355 m. The watershed of the lake has an area of 0.97 km2 and a surface flow estimated as 1.54x10 m3/a. A total of 1612 CO2 flux measurements using the accumulation chamber method were made at Santiago lake, 253 in the first campaign (November 2013), and 462, 475 and 422 in the three other campaigns, respectively, in April 2014, September 2016 and December 2016. The total CO2 flux estimated for this lake varies between 0.4 t d-1 and 0.59 t d-1, for the surveys performed, respectively, in November 2013 and September 2016; higher CO2 outputs of 1.57 and 5.87 t d-1 were calculated for the surveys carried out in April 2014 and December 2016. These higher CO2 emissions were associated with a period without water column stratification. Similarly to Santiago lake, Congro lake is located inside a maar, in the Congro Fissural Volcanic system, and has a surface area of 0.04 km2 with 18.5 m depth and a storage of about 2.4x105 m3/a. The lake, located at an altitude of 420 m, is fed by a watershed with an area of 0.33 km2 and a runoff estimated as about 8x104 m3/a. In Congro lake a total of 713 CO2 flux measurements were performed during four surveys from

Transition of neogene arc volcanism in central-western Hokkaido, viewed from K-Ar ages, style of volcanic activity, and bulk rock chemistry

Energy Technology Data Exchange (ETDEWEB)

Hirose, Wataru; Iwasaki, Miyuki; Nakagawa, Mitsuhiro [Hokkaido Univ., Sapporo (Japan)

2000-02-01

Spatial and temporal variations in late Cenozoic volcanism of southwestern Hokkaido at the northern end of NE-Japan arc have been clarified by 261 K-Ar and 76 FT ages including 49 newly determined K-Ar ages, volcanic stratigraphy, physical volcanology and whole-rock geochemistry. Arc volcanism characterized by rocks with low-Ti and Nb, and by across-arc increase in K{sub 2}O content in these rocks has continued at least since 12 Ma. Based on volcanic stratigraphy, physical volcanology and whole-rock geochemistry, volcanism after 12 Ma can be subdivided into 4 stages, 12-5, 5-1.7, and 1.7-0 Ma. The volcanism from 12 Ma to 5 Ma extended northward widely compared with distribution of Quaternary arc volcanism (1.7-0 Ma). This suggests that the arc trench junction between Kuril and NE-Japan arc's trenches was located about 100 km northward from the present position. Since around 5 Ma until 1.7 Ma, different type of volcanism under local extension field, characterized by a group of monogenetic volcanoes of alkali basalt and shield volcanoes of calc-alkaline andesite, had occurred at northern end of the volcanic region (Takikawa-Mashike region). During and after this volcanism, the northern edge of arc volcanism in the area has migrated southward. This suggests that the trench junction has migrated about 100 km southward since {approx}5 Ma. The quaternary arc volcanism (1.7-0 Ma) has been restricted at the southern part of the region. The volcanism since 12 Ma might be influenced by oblique subduction of Pacific plate beneath Kuril arc, resulting in the formation of local back arc basin at the junction and to southward migration of the trench junction. (author)

Slab dehydration in Cascadia and its relationship to volcanism, seismicity, and non-volcanic tremor

Science.gov (United States)

Delph, J. R.; Levander, A.; Niu, F.

2017-12-01

The characteristics of subduction beneath the Pacific Northwest (Cascadia) are variable along strike, leading to the segmentation of Cascadia into 3 general zones: Klamath, Siletzia, and Wrangelia. These zones show marked differences in tremor density, earthquake density, seismicity rates, and the locus and amount of volcanism in the subduction-related volcanic arc. To better understand what controls these variations, we have constructed a 3D shear-wave velocity model of the upper 80 km along the Cascadia margin from the joint inversion of CCP-derived receiver functions and ambient noise surface wave data using 900 temporary and permanent broadband seismic stations. With this model, we can investigate variations in the seismic structure of the downgoing oceanic lithosphere and overlying mantle wedge, the character of the crust-mantle transition beneath the volcanic arc, and local to regional variations in crustal structure. From these results, we infer the presence and distribution of fluids released from the subducting slab and how they affect the seismic structure of the overriding lithosphere. In the Klamath and Wrangelia zones, high seismicity rates in the subducting plate and high tremor density correlate with low shear velocities in the overriding plate's forearc and relatively little arc volcanism. While the cause of tremor is debated, intermediate depth earthquakes are generally thought to be due to metamorphic dehydration reactions resulting from the dewatering of the downgoing slab. Thus, the seismic characteristics of these zones combined with rather sparse arc volcanism may indicate that the slab has largely dewatered by the time it reaches sub-arc depths. Some of the water released during earthquakes (and possibly tremor) may percolate into the overriding plate, leading to slow seismic velocities in the forearc. In contrast, Siletzia shows relatively low seismicity rates and tremor density, with relatively higher shear velocities in the forearc

Seismological evidence for a sub-volcanic arc mantle wedge beneath the Denali volcanic gap, Alaska

Science.gov (United States)

McNamara, D.E.; Pasyanos, M.E.

2002-01-01

Arc volcanism in Alaska is strongly correlated with the 100 km depth contour of the western Aluetian Wadati-Benioff zone. Above the eastern portion of the Wadati-Benioff zone however, there is a distinct lack of volcanism (the Denali volcanic gap). We observe high Poisson's ratio values (0.29-0.33) over the entire length of the Alaskan subduction zone mantle wedge based on regional variations of Pn and Sn velocities. High Poisson's ratios at this depth (40-70 km), adjacent to the subducting slab, are attributed to melting of mantle-wedge peridotites, caused by fluids liberated from the subducting oceanic crust and sediments. Observations of high values of Poisson's ratio, beneath the Denali volcanic gap suggest that the mantle wedge contains melted material that is unable to reach the surface. We suggest that its inability to migrate through the overlying crust is due to increased compression in the crust at the northern apex of the curved Denali fault.

Volcanic Gases and Hot Spring Water to Evaluate the Volcanic Activity of the Mt. Baekdusan

Science.gov (United States)

Yun, S. H.; Lee, S.; Chang, C.

2017-12-01

This study performed the analysis on the volcanic gases and hot spring waters from the Julong hot spring at Mt. Baekdu, also known as Changbaishan on the North Korea(DPRK)-China border, during the period from July 2015 to August 2016. Also, we confirmed the errors that HCO3- concentrations of hot spring waters in the previous study (Lee et al. 2014) and tried to improve the problem. Dissolved CO2 in hot spring waters was analyzed using gas chromatograph in Lee et al.(2014). Improving this, from 2015, we used TOC-IC to analysis dissolved CO2. Also, we analyzed the Na2CO3 standard solutions of different concentrations using GC, and confirmed the correlation between the analytical concentrations and the real concentrations. However, because the analytical results of the Julong hot spring water were in discord with the estimated values based on this correlation, we can't estimate the HCO3-concentrations of 2014 samples. During the period of study, CO2/CH4 ratios in volcanic gases are gradually decreased, and this can be interpreted in two different ways. The first interpretation is that the conditions inside the volcanic edifice are changing into more reduction condition, and carbon in volcanic gases become more favorable to distribute into CH4 or CO than CO2. The second interpretation is that the interaction between volcanic gases and water becomes greater than past, and the concentrations of CO2which have much higher solubility in water decreased, relatively. In general, the effect of scrubbing of volcanic gas is strengthened during the quiet periods of volcanic activity rather than active periods. Meanwhile, the analysis of hot spring waters was done on the anion of acidic gases species, the major cations, and some trace elements (As, Cd, Re).This work was funded by the Korea Meteorological Administration Research and Development Program under Grant KMIPA 2015-3060.

Disruptive event analysis: volcanism and igneous intrusion

International Nuclear Information System (INIS)

Crowe, B.M.

1979-01-01

Three basic topics are addressed for the disruptive event analysis: first, the range of disruptive consequences of a radioactive waste repository by volcanic activity; second, the possible reduction of the risk of disruption by volcanic activity through selective siting of a repository; and third, the quantification of the probability of repository disruption by volcanic activity

Timing and compositional evolution of Late Pleistocene to Holocene volcanism within the Harrat Rahat volcanic field, Kingdom of Saudi Arabia

Science.gov (United States)

Stelten, M. E.; Downs, D. T.; Dietterich, H. R.

2017-12-01

Harrat Rahat is one of the largest ( 20,000 km2) of 15 active Cenozoic volcanic fields that stretch 3,000 km along the western Arabian Peninsula from Yemen to Syria. The Harrat Rahat volcanic field is 310 km long (N-S) by 75 km wide (E-W), and is dominated by alkalic basalts with minor hawaiite, mugearite, benmoreite, and trachyte eruptives. The timing of volcanism within greater Harrat Rahat is poorly constrained, but field relations and geochronology indicate that northern Harrat Rahat hosted the most recent eruptions. To better constrain the timing and compositional evolution of Harrat Rahat during this recent phase, we present 743 geochemical analyses, 144 40Ar/39Ar ages, and 9 36Cl exposure ages for volcanic strata from northernmost Harrat Rahat. These data demonstrate that volcanism has been ongoing from at least 1.2 Ma to the present, with the most recent eruption known from historical accounts at 1256 CE. Basalt has erupted persistently from 1.2 Ma to the present, but more evolved volcanism has been episodic. Benmoreite erupted at 1.1 Ma and between 550 to 400 ka. Trachytic volcanism has only occurred over the past 150 ka, with the most recent eruption at 5 ka. Aside from the well-documented basaltic eruption at 1256 CE, prior workers interpreted 6 additional basaltic eruptions during the Holocene. However, our 36Cl exposure ages demonstrate that these erupted between 60 to 13 ka. Interestingly, in the northern part of our field area, where the spatial density of volcanic vents is low, young volcanism (<150 ka) is dominated by basaltic eruptions. Conversely, young volcanism in the southern part of our field area, where volcanic vent density is high, is dominated by trachyte. This observation is consistent with a process wherein the time-integrated effects of basaltic influx into the crust in the south produced a mafic intrusive complex, through which younger basaltic magmas cannot ascend. Instead, these magmas stall and produce trachyte, likely through

National volcanic ash operations plan for aviation

Science.gov (United States)

,; ,

2007-01-01

The National Aviation Weather Program Strategic Plan (1997) and the National Aviation Weather Initiatives (1999) both identified volcanic ash as a high-priority informational need to aviation services. The risk to aviation from airborne volcanic ash is known and includes degraded engine performance (including flameout), loss of visibility, failure of critical navigational and operational instruments, and, in the worse case, loss of life. The immediate costs for aircraft encountering a dense plume are potentially major—damages up to $80 million have occurred to a single aircraft. Aircraft encountering less dense volcanic ash clouds can incur longer-term costs due to increased maintenance of engines and external surfaces. The overall goal, as stated in the Initiatives, is to eliminate encounters with ash that could degrade the in-flight safety of aircrews and passengers and cause damage to the aircraft. This goal can be accomplished by improving the ability to detect, track, and forecast hazardous ash clouds and to provide adequate warnings to the aviation community on the present and future location of the cloud. To reach this goal, the National Aviation Weather Program established three objectives: (1) prevention of accidental encounters with hazardous clouds; (2) reduction of air traffic delays, diversions, or evasive actions when hazardous clouds are present; and (3) the development of a single, worldwide standard for exchange of information on airborne hazardous materials. To that end, over the last several years, based on numerous documents (including an OFCMsponsored comprehensive study on aviation training and an update of Aviation Weather Programs/Projects), user forums, and two International Conferences on Volcanic Ash and Aviation Safety (1992 and 2004), the Working Group for Volcanic Ash (WG/VA), under the OFCM-sponsored Committee for Aviation Services and Research, developed the National Volcanic Ash Operations Plan for Aviation and Support of the

Ordovidan K-bentonites in the Precordillera of San Juan and its tectomasmatic significance

Science.gov (United States)

Cingolani, C.A.; Huff, W.; Bergstrom, S.; Kolata, D.

1997-01-01

A succession of approximately 35 early Middle Ordovician K-bentonite beds are exposed in the Precordillera region near the town of Jachal, in San Juan Province (at Cerro Viejo and La Chilca sections). They occur in argillaceous limestone in the upper part of the San Juan Limestone and in the interbedded shales and mudstones at the base of the overlying Los Azules Formation. Total thickness of the K-bentonite-bearing interval is 23 m and individual beds range from 1 to 65 cm thick. An essentially Arenig-Llanvirn age for the K-bentonite succession is indicated by the presence of graptolites diagnostic of the Paraglossograptus tentaculatus Zone and conodonts indicating the Eoplacognathus suecicus Zone. The bentonites consist mainly of Rl ordered illite/smectite, characteristic of most of the lower Paleozoic K-bentonites, plus volcanogenic crystals. Similar to other K-bentonites, these probably represent the distal, glass-rich portion of fall-out ash beds derived from collision zone explosive volcanism. The geochemical data and preliminary plots on the magmatic discrimination diagram indicate the parental magma was of rhyolite to trachyandesite composition. Tectonic discrimination diagrams show the setting of Cerro Viejo ash layers as falling on the boundary between volcanic arc and within plate rocks, typical of collision margin felsic volcanic rocks. U-Pb isotope dating for two zircon fractions from one sample show a lower concordia intercept of 461, +7-10 Ma coincident with the biostratigraphic age. Thus, they have important implications for the origin and early history of the allochtonous Precordillera terrane and the Pacific margin of South America. Furthermore, they are potentially important in interpretations of the paleogeographic relations of Laurentia and Gondwana during Ordovician time. ?? 1997 Asociacio??n Geolo??gica Argentina.

Climatic impact of volcanic eruptions

Science.gov (United States)

Rampino, Michael R.

1991-01-01

Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

The Ngorongoro Volcanic Highland and its relationships to volcanic deposits at Olduvai Gorge and East African Rift volcanism.

Science.gov (United States)

Mollel, Godwin F; Swisher, Carl C

2012-08-01

The Ngorongoro Volcanic Highland (NVH), situated adjacent and to the east of Olduvai Gorge in northern Tanzania, is the source of the immense quantities of lava, ignimbrite, air fall ash, and volcaniclastic debris that occur interbedded in the Plio-Pleistocene sedimentary deposits in the Laetoli and Olduvai areas. These volcanics have proven crucial to unraveling stratigraphic correlations, the age of these successions, the archaeological and paleontological remains, as well as the source materials from which the bulk of the stone tools were manufactured. The NVH towers some 2,000 m above the Olduvai and Laetoli landscapes, affecting local climate, run-off, and providing varying elevation - climate controlled ecosystem, habitats, and riparian corridors extending into the Olduvai and Laetoli lowlands. The NVH also plays a crucial role in addressing the genesis and history of East African Rift (EAR) magmatism in northern Tanzania. In this contribution, we provide age and petrochemical compositions of the major NVH centers: Lemagurut, basalt to benmorite, 2.4-2.2 Ma; Satiman, tephrite to phonolite, 4.6-3.5 Ma; Oldeani, basalt to trachyandesite, 1.6-1.5 Ma; Ngorongoro, basalt to rhyolite, 2.3-2.0 Ma; Olmoti, basalt to trachyte, 2.0-1.8 Ma; Embagai, nephelinite to phonolite, 1.2-0.6 Ma; and Engelosin, phonolite, 3-2.7 Ma. We then discuss how these correlate in time and composition with volcanics preserved at Olduvai Gorge. Finally, we place this into context with our current understanding as to the eruptive history of the NVH and relationship to East African Rift volcanism. Copyright © 2011 Elsevier Ltd. All rights reserved.

Using Satellite Observations to Evaluate the AeroCOM Volcanic Emissions Inventory and the Dispersal of Volcanic SO2 Clouds in MERRA

Science.gov (United States)

Hughes, Eric J.; Krotkov, Nickolay; da Silva, Arlindo; Colarco, Peter

2015-01-01

Simulation of volcanic emissions in climate models requires information that describes the eruption of the emissions into the atmosphere. While the total amount of gases and aerosols released from a volcanic eruption can be readily estimated from satellite observations, information about the source parameters, like injection altitude, eruption time and duration, is often not directly known. The AeroCOM volcanic emissions inventory provides estimates of eruption source parameters and has been used to initialize volcanic emissions in reanalysis projects, like MERRA. The AeroCOM volcanic emission inventory provides an eruptions daily SO2 flux and plume top altitude, yet an eruption can be very short lived, lasting only a few hours, and emit clouds at multiple altitudes. Case studies comparing the satellite observed dispersal of volcanic SO2 clouds to simulations in MERRA have shown mixed results. Some cases show good agreement with observations Okmok (2008), while for other eruptions the observed initial SO2 mass is half of that in the simulations, Sierra Negra (2005). In other cases, the initial SO2 amount agrees with the observations but shows very different dispersal rates, Soufriere Hills (2006). In the aviation hazards community, deriving accurate source terms is crucial for monitoring and short-term forecasting (24-h) of volcanic clouds. Back trajectory methods have been developed which use satellite observations and transport models to estimate the injection altitude, eruption time, and eruption duration of observed volcanic clouds. These methods can provide eruption timing estimates on a 2-hour temporal resolution and estimate the altitude and depth of a volcanic cloud. To better understand the differences between MERRA simulations and volcanic SO2 observations, back trajectory methods are used to estimate the source term parameters for a few volcanic eruptions and compared to their corresponding entry in the AeroCOM volcanic emission inventory. The nature of

Riesgos antrópicos generados por la actividad minera

Directory of Open Access Journals (Sweden)

Ana Violeta Argüello Mejía

2013-10-01

Full Text Available Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y Calacalí, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican que la minería artesanal en sus inicios constituyó una fuente de trabajo, donde sus familias también se involucraban. Actualmente, se observa que en la mayoría de las canteras se utiliza maquinaria especializada y no participan los trabajadores de la zona. Los taludes de las canteras son de 80o y 90o grados, generando amenazas para los trabajadores y moradores de las viviendas aledañas. Uno de los mayores impactos es la contaminación del aire, sin embargo, el suelo y los cursos de agua están siendo afectados por los desperdicios que produce la actividad minera. La población, que está expuesta permanentemente al polvo ocasionado por las canteras y al transporte de material, acusa enfermedades de tipo respiratorio. Así mismo, el ruido ocasionado por el transporte constituye una molestia constante para los pobladores.

Matched-filtering generalized phase contrast using LCoS pico-projectors for beam-forming

DEFF Research Database (Denmark)

Bañas, Andrew Rafael; Palima, Darwin; Glückstad, Jesper

2012-01-01

, optical lattices and other beam-shaping applications usually implemented with high-end spatial light modulators. Portable pico-projectors based on liquid crystal on silicon (LCoS) devices are used as binary phase-only spatial light modulators by carefully setting the appropriate polarization of the laser...

Assessment of volcanic hazards, vulnerability, risk and uncertainty (Invited)

Science.gov (United States)

Sparks, R. S.

2009-12-01

A volcanic hazard is any phenomenon that threatens communities . These hazards include volcanic events like pyroclastic flows, explosions, ash fall and lavas, and secondary effects such as lahars and landslides. Volcanic hazards are described by the physical characteristics of the phenomena, by the assessment of the areas that they are likely to affect and by the magnitude-dependent return period of events. Volcanic hazard maps are generated by mapping past volcanic events and by modelling the hazardous processes. Both these methods have their strengths and limitations and a robust map should use both approaches in combination. Past records, studied through stratigraphy, the distribution of deposits and age dating, are typically incomplete and may be biased. Very significant volcanic hazards, such as surge clouds and volcanic blasts, are not well-preserved in the geological record for example. Models of volcanic processes are very useful to help identify hazardous areas that do not have any geological evidence. They are, however, limited by simplifications and incomplete understanding of the physics. Many practical volcanic hazards mapping tools are also very empirical. Hazards maps are typically abstracted into hazards zones maps, which are some times called threat or risk maps. Their aim is to identify areas at high levels of threat and the boundaries between zones may take account of other factors such as roads, escape routes during evacuation, infrastructure. These boundaries may change with time due to new knowledge on the hazards or changes in volcanic activity levels. Alternatively they may remain static but implications of the zones may change as volcanic activity changes. Zone maps are used for planning purposes and for management of volcanic crises. Volcanic hazards maps are depictions of the likelihood of future volcanic phenomena affecting places and people. Volcanic phenomena are naturally variable, often complex and not fully understood. There are

Martian volcanism: A review

International Nuclear Information System (INIS)

Carr, M.H.

1987-01-01

Martian volcanism is reviewed. It is emphasized that lava plains constitute the major type of effusive flow, and can be differentiated by morphologic characteristics. Shield volcanoes, domes, and patera constitute the major constructional landforms, and recent work has suggested that explosive activity and resulting pyroclastic deposits may have been involved with formation of some of the small shields. Analysis of morphology, presumed composition, and spectroscopic data all indicate that Martian volcanism was dominantly basaltic in composition

Volcanic eruptions and solar activity

Science.gov (United States)

Stothers, Richard B.

1989-01-01

The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

Volcanic hazards of the Idaho National Engineering Laboratory and adjacent areas

International Nuclear Information System (INIS)

Hackett, W.R.; Smith, R.P.

1994-12-01

Potential volcanic hazards are assessed, and hazard zone maps are developed for the Idaho National Engineering Laboratory (INEL) and adjacent areas. The basis of the hazards assessment and mapping is the past volcanic history of the INEL region, and the apparent similarity of INEL volcanism with equivalent, well-studied phenomena in other regions of active volcanism, particularly Hawaii and Iceland. The most significant hazards to INEL facilities are associated with basaltic volcanism, chiefly lava flows, which move slowly and mainly threaten property by inundation or burning. Related hazards are volcanic gases and tephra, and ground disturbance associated with the ascent of magma under the volcanic zones. Several volcanic zones are identified in the INEL area. These zones contain most of the volcanic vents and fissures of the region and are inferred to be the most probable sites of future INEL volcanism. Volcanic-recurrence estimates are given for each of the volcanic zones based on geochronology of the lavas, together with the results of field and petrographic investigations concerning the cogenetic relationships of INEL volcanic deposits and associated magma intrusion. Annual probabilities of basaltic volcanism within the INEL volcanic zones range from 6.2 x 10 -5 per year (average 16,000-year interval between eruptions) for the axial volcanic zone near the southern INEL boundary and the Arco volcanic-rift zone near the western INEL boundary, to 1 x 10 -5 per year (average 100,000-year interval between eruptions) for the Howe-East Butte volcanic rift zone, a geologically old and poorly defined feature of the central portion of INEL. Three volcanic hazard zone maps are developed for the INEL area: lava flow hazard zones, a tephra (volcanic ash) and gas hazard zone, and a ground-deformation hazard zone. The maps are useful in land-use planning, site selection, and safety analysis

[Effects of volcanic eruptions on human health in Iceland. Review].

Science.gov (United States)

Gudmundsson, Gunnar; Larsen, Guðrun

2016-01-01

Volcanic eruptions are common in Iceland and have caused health problems ever since the settlement of Iceland. Here we describe volcanic activity and the effects of volcanic gases and ash on human health in Iceland. Volcanic gases expelled during eruptions can be highly toxic for humans if their concentrations are high, irritating the mucus membranes of the eyes and upper respiratory tract at lower concentrations. They can also be very irritating to the skin. Volcanic ash is also irritating for the mucus membranes of the eyes and upper respiratory tract. The smalles particles of volcanic ash can reach the alveoli of the lungs. Described are four examples of volcanic eruptions that have affected the health of Icelanders. The eruption of Laki volcanic fissure in 1783-1784 is the volcanic eruption that has caused the highest mortality and had the greatest effects on the well-being of Icelanders. Despite multiple volcanic eruptions during the last decades in Iceland mortality has been low and effects on human health have been limited, although studies on longterm effects are lacking. Studies on the effects of the Eyjafjallajökul eruption in 2010 on human health showed increased physical and mental symptoms, especially in those having respiratory disorders. The Directorate of Health in Iceland and other services have responded promptly to recurrent volcanic eruptions over the last few years and given detailed instructions on how to minimize the effects on the public health. Key words: volcanic eruptions, Iceland, volcanic ash, volcanic gases, health effects, mortality. Correspondence: Gunnar Guðmundsson, ggudmund@landspitali.is.

Viejos problemas y nuevos vecinos. Consecuencias de una gran reforma urbana en el barrio del Raval, Barcelona

Directory of Open Access Journals (Sweden)

Miquel Fernández González

2016-05-01

Full Text Available El barrio del Raval de Barcelona, conocido anteriormente como Distrito V y asociado a la mitificada sordidez del Barrio Chino (uno de los más populares barrios rojos de Europa, se encuentra actualmente en una fase terminal de su reforma urbanística. Esta se inició en 1988 a rebufo de la elección de Barcelona como sede de los Juegos Olímpicos de 1992. Arrancando el presente siglo, se implementó la última intervención urbanística sobre el barrio, concretamente sobre la zona de estudio, la conocida como Illa Robador. La calle d'en Robador ha sido hasta época muy reciente -y probablemente aún lo siga siendo- el nuevo epicentro y quizás el último bastión del Barrio Chino. El mito y la reforma urbanística se convocan en la etnografía que aquí se presenta. Se ha querido levantar acta de los encuentros y encontronazos entre «viejos vecinos», que han sobrevivido a toda clase de mistificaciones y estigmatizaciones, y «nuevos vecinos» atraídos por la posibilidad de vivir en un lugar céntrico, en el nuevo distrito cultural de Barcelona. Se concluye interpretando estos conflictos a la luz de lo que algunos autores llaman un nuevo colonialismo urbano.

EMBARAZO ECTÓPICO MOLAR CORNUAL: CASO CLÍNICO

OpenAIRE

Flores Acosta,Clara del Carmen; Barboza Quintana,Oralia; Vidal Gutiérrez,Oscar; Morales Martínez,Felipe

2010-01-01

Antecedentes: La incidencia de embarazo ectópico es 20/1000 embarazos y en la región cornual se presentan en el 2-4%. La mola hidatiforme ocurre en 1/1000 embarazos en EEUU y 1/500 en México. La presentación simultánea es muy rara. Se han descrito solamente 40 casos en la literatura médica, con una incidencia estimada de 0,04% de localización cornual. Caso clínico: Primigesta de 30 años, que cursando un embarazo de 8 semanas, acude de urgencia por presentar náuseas y vómitos de 1 día de evolu...

EMBARAZO ECTÓPICO CRÓNICO COMO MASA ANEXIAL

OpenAIRE

Ruvalcaba L.,Eva; Muñoz G.,David; Pérez M.,Delia

2005-01-01

Introducción: El embarazo ectópico crónico es una entidad clínico-patológica infrecuente con evolución poco clara; los estudios de imagen muestran la presencia de masa pélvica extrauterina con patrón mixto y líquido libre en fondo de saco como resultado de la ruptura de la trompa de Fallopio, sangrado, proceso inflamatorio y necrosis. Caso: Mujer de 43 años de edad, con masa anexial de patrón mixto, elevación de marcadores tumorales, útero vacío y cuadro clínico autolimitado e inespecífico de...

Stochastic Modeling of Past Volcanic Crises

Science.gov (United States)

Woo, Gordon

2018-01-01

The statistical foundation of disaster risk analysis is past experience. From a scientific perspective, history is just one realization of what might have happened, given the randomness and chaotic dynamics of Nature. Stochastic analysis of the past is an exploratory exercise in counterfactual history, considering alternative possible scenarios. In particular, the dynamic perturbations that might have transitioned a volcano from an unrest to an eruptive state need to be considered. The stochastic modeling of past volcanic crises leads to estimates of eruption probability that can illuminate historical volcanic crisis decisions. It can also inform future economic risk management decisions in regions where there has been some volcanic unrest, but no actual eruption for at least hundreds of years. Furthermore, the availability of a library of past eruption probabilities would provide benchmark support for estimates of eruption probability in future volcanic crises.

Lasers in tattoo and pigmentation control: role of the PicoSure(®) laser system.

Science.gov (United States)

Torbeck, Richard; Bankowski, Richard; Henize, Sarah; Saedi, Nazanin

2016-01-01

The use of picosecond lasers to remove tattoos has greatly improved due to the long-standing outcomes of nanosecond lasers, both clinically and histologically. The first aesthetic picosecond laser available for this use was the PicoSure(®) laser system (755/532 nm). Now that a vast amount of research on its use has been conducted, we performed a comprehensive review of the literature to validate the continued application of the PicoSure(®) laser system for tattoo removal. A PubMed search was conducted using the term "picosecond" combined with "laser", "dermatology", and "laser tattoo removal". A total of 13 articles were identified, and ten of these met the inclusion criteria for this review. The majority of studies showed that picosecond lasers are an effective and safe treatment mode for the removal of tattoo pigments. Several studies also indicated potential novel applications of picosecond lasers in the removal of various tattoo pigments (eg, black, red, and yellow). Adverse effects were generally mild, such as transient hypopigmentation or blister formation, and were rarely more serious, such as scarring and/or textural change. Advancements in laser technologies and their application in cutaneous medicine have revolutionized the field of laser surgery. Computational modeling provides evidence that the optimal pulse durations for tattoo ink removal are in the picosecond domain. It is recommended that the PicoSure(®) laser system continue to be used for safe and effective tattoo removal, including for red and yellow pigments.

Rate of volcanism on Venus

International Nuclear Information System (INIS)

Fegley, B. Jr.; Prinn, R.G.

1988-07-01

The maintenance of the global H 2 SO 4 clouds on Venus requires volcanism to replenish the atmospheric SO 2 which is continually being removed from the atmosphere by reaction with calcium minerals on the surface of Venus. The first laboratory measurements of the rate of one such reaction, between SO 2 and calcite (CaCO 3 ) to form anhydrite (CaSO 4 ), are reported. If the rate of this reaction is representative of the SO 2 reaction rate at the Venus surface, then we estimate that all SO 2 in the Venus atmosphere (and thus the H 2 SO 4 clouds) will be removed in 1.9 million years unless the lost SO 2 is replenished by volcanism. The required rate of volcanism ranges from about 0.4 to about 11 cu km of magma erupted per year, depending on the assumed sulfur content of the erupted material. If this material has the same composition as the Venus surface at the Venera 13, 14 and Vega 2 landing sites, then the required rate of volcanism is about 1 cu km per year. This independent geochemically estimated rate can be used to determine if either (or neither) of the two discordant (2 cu km/year vs. 200 to 300 cu km/year) geophysically estimated rates is correct. The geochemically estimated rate also suggests that Venus is less volcanically active than the Earth

Global volcanic aerosol properties derived from emissions, 1990-2014, using CESM1(WACCM): VOLCANIC AEROSOLS DERIVED FROM EMISSIONS

Energy Technology Data Exchange (ETDEWEB)

Mills, Michael J. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Schmidt, Anja [School of Earth and Environment, University of Leeds, Leeds UK; Easter, Richard [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Solomon, Susan [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge Massachusetts USA; Kinnison, Douglas E. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Ghan, Steven J. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Neely, Ryan R. [School of Earth and Environment, University of Leeds, Leeds UK; National Centre for Atmospheric Science, University of Leeds, Leeds UK; Marsh, Daniel R. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Conley, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Bardeen, Charles G. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Gettelman, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA

2016-03-06

Accurate representation of global stratospheric aerosol properties from volcanic and non-volcanic sulfur emissions is key to understanding the cooling effects and ozone-loss enhancements of recent volcanic activity. Attribution of climate and ozone variability to volcanic activity is of particular interest in relation to the post-2000 slowing in the apparent rate of global average temperature increases, and variable recovery of the Antarctic ozone hole. We have developed a climatology of global aerosol properties from 1990 to 2014 calculated based on volcanic and non-volcanic emissions of sulfur sources. We have complied a database of volcanic SO2 emissions and plume altitudes for eruptions between 1990 and 2014, and a new prognostic capability for simulating stratospheric sulfate aerosols in version 5 of the Whole Atmosphere Community Climate Model, a component of the Community Earth System Model. Our climatology shows remarkable agreement with ground-based lidar observations of stratospheric aerosol optical depth (SAOD), and with in situ measurements of aerosol surface area density (SAD). These properties are key parameters in calculating the radiative and chemical effects of stratospheric aerosols. Our SAOD climatology represents a significant improvement over satellite-based analyses, which ignore aerosol extinction below 15 km, a region that can contain the vast majority of stratospheric aerosol extinction at mid- and high-latitudes. Our SAD climatology significantly improves on that provided for the Chemistry-Climate Model Initiative, which misses 60% of the SAD measured in situ. Our climatology of aerosol properties is publicly available on the Earth System Grid.

Indirect Climatic Effects of Major Volcanic Eruptions

Science.gov (United States)

Hofmann, D. J.

2007-05-01

The direct effects on climate, related to atmospheric emissions to the atmosphere following major volcanic eruptions, are well-known although the sparseness of such eruptions make detailed study on the range of such variations difficult. In general terms, infrared absorption by volcanic emissions to the stratosphere result in local heating early in the event when gaseous sulfur compounds exist. This early period is followed by gas to particle conversion, on a time scale of 1-2 months, promoting the formation of sulfuric acid-water droplets. Coagulation and droplet growth result in the "volcanic stratospheric aerosol layer" which is related to the predominant direct climatic effect of large eruptions, the cooling of the troposphere by backscattering of solar visible radiation to space with a recovery time scale of 1-2 years. In this paper we will discuss some of the less-known "indirect" effects of the volcanic stratospheric aerosol on climate. We label them indirect as they act on climate through intermediary atmospheric constituents. The intermediaries in the volcanic indirect climatic effect are generally atmospheric greenhouse gases or other atmospheric gases and conditions which affect greenhouse gases. For example, cooling of the troposphere following major eruptions reduces the growth rate of atmospheric carbon dioxide related to respiration by the terrestrial biosphere. In addition, redirection of part of the direct solar beam into diffuse radiation by the volcanic stratospheric aerosol stimulates plant photosynthesis, further reducing the carbon dioxide growth rate. The growth rate of the second-most important atmospheric greenhouse gas, methane, is also affected by volcanic emissions. Volcanic stratospheric aerosol particles provide surface area which catalyzes heterogeneous chemical reactions thus stimulating removal of stratospheric ozone, also a greenhouse gas. Although major droughts usually related to ENSO events have opposite effects on carbon

Escala de VO2pico em adolescentes obesos e não-Obesos por diferentes métodos Escala de VO2pico en adolescentes obesos y no obesos por diferentes métodos Scale of VO2peak in obese and non-obese adolescents by different methods

Directory of Open Access Journals (Sweden)

Gerusa Eisfeld Milano

2009-12-01

Full Text Available FUNDAMENTO: O consumo de oxigênio de pico (VO2pico pode ser definido como a maior taxa de consumo de oxigênio durante exercício exaustivo ou máximo. A avaliação da aptidão aeróbica pode ser expressa como relativa à massa corporal, mas esse procedimento pode não remover completamente as diferenças quando indivíduos pesados são avaliados. Assim, o procedimento com escala alométrica é uma estratégia atraente para comparar indivíduos com grandes diferenças em massa corporal. OBJETIVO: Investigar o VO2pico em indivíduos obesos e não-obesos usando o método de correção de massa corporal (convencional e escala alométrica (método alométrico e, como esses métodos são aplicados quando indivíduos de ambos os sexos se exercitam em uma esteira ergométrica. MÉTODOS: O VO2pico relativo ao peso corporal e pelo método alométrico foi comparado em 54 adolescentes obesos e 33 não-obesos (10 a 16 anos. Calorimetria indireta foi usada para avaliar o VO2pico durante um teste máximo. O expoente alométrico foi calculado levando-se em consideração a massa corporal individual. Então o VO2pico foi corrigido pelo expoente alométrico. As comparações foram realizadas usando-se two-way ANOVA para medidas repetidas (p0,05. Entretanto, o VO2pico calculado pelo método convencional foi maior (p0,05 entre os grupos. CONCLUSÃO: Indivíduos obesos apresentaram VO2pico mais baixo do que os não-obesos, quando avaliados pelo método convencional. Entretanto, quando o método da escala alométrica foi aplicado, as diferenças desapareceram.FUNDAMENTO: El consumo pico de oxígeno (VO2pico puede ser definido como la mayor tasa de consumo de oxígeno durante ejercicio exhaustivo o máximo. La evaluación de aptitud aeróbica puede expresarse como relativa a la masa corporal, pero ese procedimiento puede no resolver completamente las diferencias cuando se evalúan individuos pesados. Por ello, el procedimiento con escala alométrica es una

Volcanism Studies: Final Report for the Yucca Mountain Project

International Nuclear Information System (INIS)

Crowe, Bruce M.; Perry, Frank V.; Valentine, Greg A.; Bowker, Lynn M.

1998-01-01

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. An assessment of the risk of future volcanic activity is one of many site characterization studies that must be completed to evaluate the Yucca Mountain site for potential long-term storage of high-level radioactive waste. The presence of several basaltic volcanic centers in the Yucca Mountain region of Pliocene and Quaternary age indicates that there is a finite risk of a future volcanic event occurring during the 10,000-year isolation period of a potential repository. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt ( than about 7 x 10 -8 events yr -1 . Simple probability estimates are used to assess possible implications of not drilling aeromagnetic anomalies in the Amargosa Valley. The sensitivity of the disruption probability to the location of northeast boundaries of volcanic zones near the Yucca Mountain sit

Disponibilidad de medicamentos psicotrópicos en establecimientos del Ministerio de Salud del Perú, 2011

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Dominic Hodgkin

Full Text Available Objetivos. Describir la disponibilidad de medicamentos psicotrópicos para el tratamiento de trastornos mentales en el Perú en los establecimientos del Ministerio de Salud. Materiales y métodos. Se analizaron informes mensuales de inventarios de medicamentos disponibles y de consumo en los establecimientos del Ministerio de Salud durante el año 2011. Usando un diseño transversal, se determinó la disponibilidad de siete clases de medicamentos psicotrópicos, distinguiendo el nivel de atención de los establecimientos, y el nivel de autonomía de decisión para la compra de medicamentos. Resultados. Los medicamentos ansiolíticos estuvieron disponibles en los establecimientos de salud de todos los niveles de atención. Los antidepresivos y antipsicóticos se encontraron disponibles en alrededor de dos tercios de los hospitales, y en menos del 20% de centros y puestos de salud. Las otras cuatro clases de medicamentos psicotrópicos (litio, hipnóticos y sedantes, psicoestimulantes/TDAH y drogas antidemencia solo estuvieron disponibles en hospitales y mas no así en centros y puestos de salud. El 5% de los hospitales contó con suministro suficiente para satisfacer la demanda durante todos los meses del año. Conclusiones. Existe una importante brecha en la disponibilidad de medicamentos psicotrópicos en los establecimientos del Ministerio de Salud del Perú. Se observa esta situación tanto en hospitales como en el nivel primario de atención. Es necesario tomar acciones en la política y gestión de salud, incluyendo más financiamiento y una mayor capacitación en salud mental para el personal de la atención primaria, entre otras iniciativas.

Mainshock-Aftershocks Clustering Detection in Volcanic Regions

Science.gov (United States)

Garza Giron, R.; Brodsky, E. E.; Prejean, S. G.

2017-12-01

Crustal earthquakes tend to break their general Poissonean process behavior by gathering into two main kinds of seismic bursts: swarms and mainshock-aftershocks sequences. The former is commonly related to volcanic or geothermal processes whereas the latter is a characteristic feature of tectonically driven seismicity. We explore the mainshock-aftershock clustering behavior of different active volcanic regions in Japan and its comparison to non-volcanic regions. We find that aftershock production in volcanoes shows mainshock-aftershocks clustering similar to what is observed in non-volcanic areas. The ratio of volanic areas that cluster in mainshock-aftershocks sequences vs the areas that do not is comparable to the ratio of non-volcanic regions that show clustering vs the ones that do not. Furthermore, the level of production of aftershocks for most volcanic areas where clustering is present seems to be of the same order of magnitude, or slightly higher, as the median of the non-volcanic regions. An interesting example of highly aftershock-productive volcanoes emerges from the 2000 Miyakejima dike intrusion. A big seismic cluster started to build up rapidly in the south-west flank of Miyakejima to later propagate to the north-west towards the Kozushima and Niijima volcanoes. In Miyakejima the seismicity showed a swarm-like signature with a constant earthquake rate, whereas Kozushima and Niijima both had expressions of highly productive mainshock-aftershocks sequences. These findings are surprising given the alternative mechanisms available in volcanic systems for releasing deviatoric strain. We speculate that aftershock behavior might hold a relationship with the rheological properties of the rocks of each system and with the capacity of a system to accumulate or release the internal pressures caused by magmatic or hydrothermal systems.

Neogene volcanism in Gutai Mts. (Eastern Carpathains: a review

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Marinel Kovacs

2003-04-01

Full Text Available Two types of volcanism developed in Gutâi Mts. (inner volcanic chain of Eastern Carpathians: a felsic, extensional/“back-arc” type and an intermediate, arc type. The felsic volcanism of explosive origin, consisting of caldera-related rhyolitic ignimbrites and resedimented volcaniclastics, had taken place during Early-Middle Badenian and Early Sarmatian. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The geochemical study on the volcanic rocks shows the calc-alkaline character of both felsic and intermediate volcanism and typical subduction zones geochemical signatures for the intermediate one. The felsic volcanism shows affinities with subduction-related rocks as well. The main petrogenetic process in Gutâi Mts. was crustal assimilation, strongly constrained by trace element and isotope geochemistry.

Petrology and geochronology of metamorphosed volcanic rocks and a middle Cretaceous volcanic neck in the east-central Sierra Nevada, California.

Science.gov (United States)

Kistler, R.W.; Swanson, S.E.

1981-01-01

Metamorphosed Mesozoic volcanic rocks from the E-central Sierra Nevada range in composition from basalt to rhyolite and have ages, based on whole rock Rb-Sr and U-Pb zircon dating, of about 237- 224, 185, 163, 134, and 100Ma. The major plutons of the batholith in this area are of Triassic (215-200Ma) and Cretaceous (94-80Ma) ages. Initial 87Sr/86Sr values for the metamorphosed volcanic rocks of the area are in the range from 0.7042 to 0.7058 and are generally different from the values for the surrounding batholithic rocks (0.7056-0.7066). A circular, zoned granitic pluton, with an outcrop area of 2.5km2, similar in appearance to a ring dike complex, was apparently a conduit for some or possibly all of the middle-Cretaceous metamorphosed volcanic rocks exposed about 5km to the S in the western part of the Ritter Range. Samples from the metamorphosed volcanic rocks and the pluton yield a Rb/Sr whole rock isochron age of 99.9+ or -2.2Ma with an intitial 87Sr/86Sr of 0.7048+ or -0.00001. Major element variation diagrams of the pluton and volcanic rocks define coincident compositional trends. The ages of volcanic events relative to the ages of the major intrusive epochs and the major element and isotopic compositions of the volcanic rocks relative to the major plutons indicate that the volcanic rocks are not simply or directly related to the major plutons in the Sierra Nevada. -from Authors

Volcanic Characteristics of Kueishantao in Northeast Taiwan and Their Implications

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Ching-Lung Chiu

2010-01-01

Full Text Available Kueishantao (KST is a small offshore volcanic island located at the southernmost part of the Okinawa Trough. In this study, we conducted a detailed mapping incorporating the new high resolution LiDAR DTM laser scanning device to accurately construct a volcanic sequence. A new 1/5000 geological map was established. One primary volcanic cone, composed of layers of both lava flows and pyroclastic rocks constituted the major edifice of KST. The other minor volcanic cone, which consists of volcanic lapillis and blocks, is seated to the east of the main cone. The escarped and nearly straight coast in the southern part of the KST indicates that the volcano suffered a large post-volcanic edifice collapse erasing nearly one half of the volume of both volcanic cones. The increase in the abundance of the xenoliths of sedimentary rocks from the lower to the upper part of the volcanic sequence indicates that the formation of volcanic rocks of the KST involved an intensification of crustal contamination. The possibility of volcanic eruption can not be excluded in the future based on the present thermolu¬minescene age data of 7 ka. The associated eruptive ash fall and tsunami induced by the further collapse of the KST volcanic edifice might have great influence to the adjacent inland. Thus, long-term monitoring of volcanic activities around KST should be required for future hazard assessments.

The Valle de Bravo Volcanic Field. A monogenetic field in the central front of the Mexican Volcanic Belt

Science.gov (United States)

Aguirre-Diaz, G. J.; Jaimes-Viera, M. D.; Nieto-Obreg¢n, J.; Lozano-Santacruz, R.

2003-12-01

The Valle de Bravo volcanic field, VBVF, is located in the central-southern front of the Mexican Volcanic Belt just to the southwest of Nevado de Toluca volcano. The VBVF covers 3,703 square Km and includes at least 122 cinder cones, 1 shield volcano, several domes, and the 2 volcanic complexes of Zitacuaro and Villa de Allende. Morphometric parameters calibrated with isotopic ages of the volcanic products indicate four groups or units for the VBVF, Pliocene domes and lava flows, undifferentiated Pleistocene lava flows,> 40 Ka cones and lavas, 40 to 25 Ka cones and lavas, 25 to 10 Ka cones and lavas, and < 10 Ka cones and lavas. Whole-rock chemistry shows that all products of the VBVF range from basaltic andesites to dacites. No basalts were found, in spite of many units are olivine-rich and large some with large weight percent contents of MgO, 1 to 9. There is the possibility that some or all of the olivines in some samples could be xenocrysts. Some andesites are high in Sr, 1000 to 1800 ppm, that correlates with relatively high values of Ba, Cr, Ni, Cu, CaO and MgO. Y and Nb have the typical low values for orogenic rocks. The only shield volcano of the VBVF has a base of 9 Km, and its composition is practically the average composition of the whole field. Stratigraphycally, it is one of the earlier events of the VBVF. Compared with other volcanic fields of the Mexican Volcanic Belt, it lacks basalts and alkalic rocks. All volcanism of this field is calcalkaline

Assessment of the atmospheric impact of volcanic eruptions

Science.gov (United States)

Sigurdsson, H.

1988-01-01

The dominant global impact of volcanic activity is likely to be related to the effects of volcanic gases on the Earth's atmosphere. Volcanic gas emissions from individual volcanic arc eruptions are likely to cause increases in the stratospheric optical depth that result in surface landmass temperature decline of 2 to 3 K for less than a decade. Trachytic and intermediate magmas are much more effective in this regard than high-silica magmas, and may also lead to extensive ozone depletion due to effect of halogens and magmatic water. Given the assumed relationship between arc volcanism and subduction rate, and the relatively small variation in global spreading rates in the geologic record, it is unlikely that the rates of arc volcanism have varied greatly during the Cenozoic. Hotspot related basaltic fissure eruptions in the subaerial environment have a higher mass yield of sulfur, but lofting of the valcanic aerosol to levels above the tropopause is required for a climate impact. High-latitude events, such as the Laki 1783 eruption can easily penetrate the tropopause and enter the stratosphere, but formation of a stratospheric volcanic aerosol form low-latitude effusive basaltic eruptions is problematical, due to the elevated low-latitude tropopause. Due to the high sulfur content of hotspot-derived basaltic magmas, their very high mass eruption rates and the episodic behavior, hotspots must be regarded as potentially major modifiers of Earth's climate through the action of their volcanic volatiles on the chemistry and physics of the atmosphere.

A Volcanic Hydrogen Habitable Zone

International Nuclear Information System (INIS)

Ramirez, Ramses M.; Kaltenegger, Lisa

2017-01-01

The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N_2–CO_2–H_2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO_2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H_2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N_2–CO_2–H_2O–H_2) can be sustained as long as volcanic H_2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H_2 warming is reduced in dense H_2O atmospheres. The atmospheric scale heights of such volcanic H_2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

A Volcanic Hydrogen Habitable Zone

Energy Technology Data Exchange (ETDEWEB)

Ramirez, Ramses M.; Kaltenegger, Lisa, E-mail: rmr277@cornell.edu [Carl Sagan Institute, Cornell University, Ithaca, NY (United States)

2017-03-01

The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N{sub 2}–CO{sub 2}–H{sub 2}O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO{sub 2} outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H{sub 2} can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N{sub 2}–CO{sub 2}–H{sub 2}O–H{sub 2}) can be sustained as long as volcanic H{sub 2} output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H{sub 2} warming is reduced in dense H{sub 2}O atmospheres. The atmospheric scale heights of such volcanic H{sub 2} atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

Large-scale volcanism associated with coronae on Venus

Science.gov (United States)

Roberts, K. Magee; Head, James W.

1993-01-01

The formation and evolution of coronae on Venus are thought to be the result of mantle upwellings against the crust and lithosphere and subsequent gravitational relaxation. A variety of other features on Venus have been linked to processes associated with mantle upwelling, including shield volcanoes on large regional rises such as Beta, Atla and Western Eistla Regiones and extensive flow fields such as Mylitta and Kaiwan Fluctus near the Lada Terra/Lavinia Planitia boundary. Of these features, coronae appear to possess the smallest amounts of associated volcanism, although volcanism associated with coronae has only been qualitatively examined. An initial survey of coronae based on recent Magellan data indicated that only 9 percent of all coronae are associated with substantial amounts of volcanism, including interior calderas or edifices greater than 50 km in diameter and extensive, exterior radial flow fields. Sixty-eight percent of all coronae were found to have lesser amounts of volcanism, including interior flooding and associated volcanic domes and small shields; the remaining coronae were considered deficient in associated volcanism. It is possible that coronae are related to mantle plumes or diapirs that are lower in volume or in partial melt than those associated with the large shields or flow fields. Regional tectonics or variations in local crustal and thermal structure may also be significant in determining the amount of volcanism produced from an upwelling. It is also possible that flow fields associated with some coronae are sheet-like in nature and may not be readily identified. If coronae are associated with volcanic flow fields, then they may be a significant contributor to plains formation on Venus, as they number over 300 and are widely distributed across the planet. As a continuation of our analysis of large-scale volcanism on Venus, we have reexamined the known population of coronae and assessed quantitatively the scale of volcanism associated

Submarine Volcanic Eruptions and Potential Analogs for Venus

Science.gov (United States)

Wilson, L.; Mouginismark, P. J.; Fryer, P.; Gaddis, L. R.

1985-01-01

As part of an analysis program to better understand the diversity of volcanic processes on the terrestrial planets, an investigation of the volcanic landforms which exist on the Earth's ocean floor was initiated. In part, this analysis is focused toward gaining a better understanding of submarine volcanic landforms in their own right, but also it is hoped that these features may show similarities to volcanic landforms on Venus, due to the high ambient water (Earth) and atmospheric (Venus) pressures. A series of numerical modelling experiments was performed to investigate the relative importance of such attributes as water pressure and temperature on the eruption process, and to determine the rate of cooling and emplacement of lava flows in the submarine environment. Investigations to date show that the confining water pressure and the buoyancy effects of the surrounding water significantly affect the styles of volcanism on the ocean floor. In the case of Venusian volcanism, confining pressures will not be as great as that found at the ocean's abyssal plains, but nevertheless the general trend toward reducing magma vesiculation will hold true for Venus as well as the ocean floor. Furthermore, other analogs may also be found between submarine volcanism and Venusian activity.

Constructional Volcanic Edifices on Mercury: Candidates and Hypotheses of Formation

Science.gov (United States)

Wright, Jack; Rothery, David A.; Balme, Matthew R.; Conway, Susan J.

2018-04-01

Mercury, a planet with a predominantly volcanic crust, has perplexingly few, if any, constructional volcanic edifices, despite their common occurrence on other solar system bodies with volcanic histories. Using image and topographical data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, we describe two small (Earth and the Moon. Though we cannot definitively conclude that these landforms are volcanic, the paucity of constructional volcanic edifices on Mercury is intriguing in itself. We suggest that this lack is because volcanic eruptions with sufficiently low eruption volumes, rates, and flow lengths, suitable for edifice construction, were highly spatiotemporally restricted during Mercury's geological history. We suggest that volcanic edifices may preferentially occur in association with late-stage, postimpact effusive volcanic deposits. The European Space Agency/Japan Aerospace Exploration Agency BepiColombo mission to Mercury will be able to investigate further our candidate volcanic edifices; search for other, as-yet unrecognized edifices beneath the detection limits of MESSENGER data; and test our hypothesis that edifice construction is favored by late-stage, low-volume effusive eruptions.

Nursing Research, CER, PICO and PCORI.

Science.gov (United States)

Patel, Darpan I

2018-01-01

Community and public health nurse researchers encompass a unique cohort of nurse researchers that have the skills and capacity to lead projects and programs of science centered on improvement of patient outcomes through methods of comparative effectiveness research (CER). CER, as a general method, has been taught to all nurses in the form of the PICO question to improve evidence-based practices. As the climate for funding becomes more and more competitive, nurse researchers are primed to lead the change in improving patient outcomes through patient centered outcomes research (PCOR). However, the number of projects funded by agencies like the Patient Centered Outcomes Research Institute, fall well below the capabilities of the field. The purpose of this commentary is to promote the field of PCOR and encourage novice and experienced nurse researchers to apply for funding from the PCORI by introducing different methods for building capacity and promoting engagement in the national conversations of PCOR and CER.

REKF and RUKF for pico satellite attitude estimation in the presence of measurement faults

Institute of Scientific and Technical Information of China (English)

Halil Ersin Söken; Chingiz Hajiyev

2014-01-01

When a pico satel ite is under normal operational condi-tions, whether it is extended or unscented, a conventional Kalman filter gives sufficiently good estimation results. However, if the measurements are not reliable because of any kind of malfunc-tions in the estimation system, the Kalman filter gives inaccurate results and diverges by time. This study compares two different robust Kalman filtering algorithms, robust extended Kalman filter (REKF) and robust unscented Kalman filter (RUKF), for the case of measurement malfunctions. In both filters, by the use of de-fined variables named as the measurement noise scale factor, the faulty measurements are taken into the consideration with a smal weight, and the estimations are corrected without affecting the characteristic of the accurate ones. The proposed robust Kalman filters are applied for the attitude estimation process of a pico satel-lite, and the results are compared.

Age of the Auckland Volcanic Field

International Nuclear Information System (INIS)

Lindsay, J.; Leonard, G.S.

2009-01-01

In 2008 a multi-disciplinary research programme was launched, a GNS Science-University of Auckland collaboration with the aim of DEtermining VOlcanic Risk in Auckland (DEVORA). A major aspiration of DEVORA is development of a probabilistic hazard model for the Auckland Volcanic Field (AVF). This will be achieved by investigating past eruption magnitude-frequency relationships and comparing these with similar data from analogous volcanic fields. A key data set underpinning this is an age database for the AVF. To this end a comprehensive dating campaign is planned as part of DEVORA. This report, Age of the Auckland Volcanic Field, is a synthesis of all currently available age data for the AVF. It represents one of several reports carried out as part of the 'synthesis' phase of DEVORA, whereby existing data from all previous work is collated and summarised, so that gaps in current knowledge can be identified and addressed. (author). 60 refs., 7 figs., 31 tabs.

Sediment-infill volcanic breccia from the Neoarchean Shimoga greenstone terrane, western Dharwar Craton: Implications on pyroclastic volcanism and sedimentation in an active continental margin

Science.gov (United States)

Manikyamba, C.; Saha, Abhishek; Ganguly, Sohini; Santosh, M.; Lingadevaru, M.; Rajanikanta Singh, M.; Subba Rao, D. V.

2014-12-01

We report sediment-infill volcanic breccia from the Neoarchean Shimoga greenstone belt of western Dharwar Craton which is associated with rhyolites, chlorite schists and pyroclastic rocks. The pyroclastic rocks of Yalavadahalli area of Shimoga greenstone belt host volcanogenic Pb-Cu-Zn mineralization. The sediment-infill volcanic breccia is clast-supported and comprises angular to sub-angular felsic volcanic clasts embedded in a dolomitic matrix that infilled the spaces in between the framework of volcanic clasts. The volcanic clasts are essentially composed of alkali feldspar and quartz with accessory biotite and opaques. These clasts have geochemical characteristics consistent with that of the associated potassic rhyolites from Daginkatte Formation. The rare earth elements (REE) and high field strength element (HFSE) compositions of the sediment-infill volcanic breccia and associated mafic and felsic volcanic rocks suggest an active continental margin setting for their generation. Origin, transport and deposition of these rhyolitic clasts and their aggregation with infiltrated carbonate sediments may be attributed to pyroclastic volcanism, short distance transportation of felsic volcanic clasts and their deposition in a shallow marine shelf in an active continental margin tectonic setting where the rhyolitic clasts were cemented by carbonate material. This unique rock type, marked by close association of pyroclastic volcanic rocks and shallow marine shelf sediments, suggest shorter distance between the ridge and shelf in the Neoarchean plate tectonic scenario.

Volcanic Supersites as cross-disciplinary laboratories

Science.gov (United States)

Provenzale, Antonello; Beierkuhnlein, Carl; Giamberini, Mariasilvia; Pennisi, Maddalena; Puglisi, Giuseppe

2017-04-01

Volcanic Supersites, defined in the frame of the GEO-GSNL Initiative, are usually considered mainly for their geohazard and geological characteristics. However, volcanoes are extremely challenging areas from many other points of view, including environmental and climatic properties, ecosystems, hydrology, soil properties and biogeochemical cycling. Possibly, volcanoes are closer to early Earth conditions than most other types of environment. During FP7, EC effectively fostered the implementation of the European volcano Supersites (Mt. Etna, Campi Flegrei/Vesuvius and Iceland) through the MED-SUV and FUTUREVOLC projects. Currently, the large H2020 project ECOPOTENTIAL (2015-2019, 47 partners, http://www.ecopotential-project.eu/) contributes to GEO/GEOSS and to the GEO ECO Initiative, and it is devoted to making best use of remote sensing and in situ data to improve future ecosystem benefits, focusing on a network of Protected Areas of international relevance. In ECOPOTENTIAL, remote sensing and in situ data are collected, processed and used for a better understanding of the ecosystem dynamics, analysing and modelling the effects of global changes on ecosystem functions and services, over an array of different ecosystem types, including mountain, marine, coastal, arid and semi-arid ecosystems, and also areas of volcanic origin such as the Canary and La Reunion Islands. Here, we propose to extend the network of the ECOPOTENTIAL project to include active Volcanic Supersites, such as Mount Etna and other volcanic Protected Areas, and we discuss how they can be included in the framework of the ECOPOTENTIAL workflow. A coordinated and cross-disciplinary set of studies at these sites should include geological, biological, ecological, biogeochemical, climatic and biogeographical aspects, as well as their relationship with the antropogenic impact on the environment, and aim at the global analysis of the volcanic Earth Critical Zone - namely, the upper layer of the Earth

O abuso de medicamentos psicotrópicos na contemporaneidade

OpenAIRE

Pelegrini,Marta Regueira Fonseca

2003-01-01

O artigo propõe uma análise crítica do fenômeno do abuso de medicamentos psicotrópicos na atualidade. A base teórica é a psicanálise. A argumentação parte da discussão da subjetividade contemporânea, resgatando o conceito de mal-estar na civilização em Freud, para elucidar algumas das causas e dos efeitos desse fato atual. The article propose a critical analyse about the abuse of psychotropy medicines, usuing the theory of psychoanalyses and the discussion about the subjectivite process....

Lidar detection of carbon dioxide in volcanic plumes

Science.gov (United States)

Fiorani, Luca; Santoro, Simone; Parracino, Stefano; Maio, Giovanni; Del Franco, Mario; Aiuppa, Alessandro

2015-06-01

Volcanic gases give information on magmatic processes. In particular, anomalous releases of carbon dioxide precede volcanic eruptions. Up to now, this gas has been measured in volcanic plumes with conventional measurements that imply the severe risks of local sampling and can last many hours. For these reasons and for the great advantages of laser sensing, the thorough development of volcanic lidar has been undertaken at the Diagnostics and Metrology Laboratory (UTAPRAD-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In fact, lidar profiling allows one to scan remotely volcanic plumes in a fast and continuous way, and with high spatial and temporal resolution. Two differential absorption lidar instruments will be presented in this paper: BILLI (BrIdge voLcanic LIdar), based on injection seeded Nd:YAG laser, double grating dye laser, difference frequency mixing (DFM) and optical parametric amplifier (OPA), and VULLI (VULcamed Lidar), based on injection seeded Nd:YAG laser and optical parametric oscillator (OPO). The first one is funded by the ERC (European Research Council) project BRIDGE and the second one by the ERDF (European Regional Development Fund) project VULCAMED. While VULLI has not yet been tested in a volcanic site, BILLI scanned the gas emitted by Pozzuoli Solfatara (Campi Flegrei volcanic area, Naples, Italy) during a field campaign carried out from 13 to 17 October 2014. Carbon dioxide concentration maps were retrieved remotely in few minutes in the crater area. Lidar measurements were in good agreement with well-established techniques, based on different operating principles. To our knowledge, it is the first time that carbon dioxide in a volcanic plume is retrieved by lidar, representing the first direct measurement of this kind ever performed on an active volcano and showing the high potential of laser remote sensing in geophysical research.

Contribuições para a construção de taxonomias de tópicos em domínios restritos utilizando aprendizado estatístico

OpenAIRE

Maria Fernanda Moura

2009-01-01

A mineração de textos vem de encontro à realidade atual de se compreender e utilizar grandes massas de dados textuais. Uma forma de auxiliar a compreensão dessas coleções de textos é construir taxonomias de tópicos a partir delas. As taxonomias de tópicos devem organizar esses documentos, preferencialmente em hierarquias, identificando os grupos obtidos por meio de descritores. Construir manual, automática ou semi-automaticamente taxonomias de tópicos de qualidade é uma tarefa nada trivial. A...

Topographic stress and catastrophic collapse of volcanic islands

Science.gov (United States)

Moon, S.; Perron, J. T.; Martel, S. J.

2017-12-01

Flank collapse of volcanic islands can devastate coastal environments and potentially induce tsunamis. Previous studies have suggested that factors such as volcanic eruption events, gravitational spreading, the reduction of material strength due to hydrothermal alteration, steep coastal cliffs, or sea level change may contribute to slope instability and induce catastrophic collapse of volcanic flanks. In this study, we examine the potential influence of three-dimensional topographic stress perturbations on flank collapses of volcanic islands. Using a three-dimensional boundary element model, we calculate subsurface stress fields for the Canary and Hawaiian islands to compare the effects of stratovolcano and shield volcano shapes on topographic stresses. Our model accounts for gravitational stresses from the actual shapes of volcanic islands, ambient stress in the underlying plate, and the influence of pore water pressure. We quantify the potential for slope failure of volcanic flanks using a combined model of three-dimensional topographic stress and slope stability. The results of our analysis show that subsurface stress fields vary substantially depending on the shapes of volcanoes, and can influence the size and spatial distribution of flank failures.

Lasers in tattoo and pigmentation control: role of the PicoSure® laser system

Science.gov (United States)

Torbeck, Richard; Bankowski, Richard; Henize, Sarah; Saedi, Nazanin

2016-01-01

Background and objectives The use of picosecond lasers to remove tattoos has greatly improved due to the long-standing outcomes of nanosecond lasers, both clinically and histologically. The first aesthetic picosecond laser available for this use was the PicoSure® laser system (755/532 nm). Now that a vast amount of research on its use has been conducted, we performed a comprehensive review of the literature to validate the continued application of the PicoSure® laser system for tattoo removal. Study design and methods A PubMed search was conducted using the term “picosecond” combined with “laser”, “dermatology”, and “laser tattoo removal”. Results A total of 13 articles were identified, and ten of these met the inclusion criteria for this review. The majority of studies showed that picosecond lasers are an effective and safe treatment mode for the removal of tattoo pigments. Several studies also indicated potential novel applications of picosecond lasers in the removal of various tattoo pigments (eg, black, red, and yellow). Adverse effects were generally mild, such as transient hypopigmentation or blister formation, and were rarely more serious, such as scarring and/or textural change. Conclusion Advancements in laser technologies and their application in cutaneous medicine have revolutionized the field of laser surgery. Computational modeling provides evidence that the optimal pulse durations for tattoo ink removal are in the picosecond domain. It is recommended that the PicoSure® laser system continue to be used for safe and effective tattoo removal, including for red and yellow pigments. PMID:27194919

TASAS DE RECAMBIO FLORÍSTICO DE GÉNEROS EN BOSQUES MONTANOS DEL NEOTRÓPICO

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López Wilson

2010-06-01

Full Text Available Se evaluó la tasa de recambio fl orístico en bosques de alta montaña (por encima delos 1500 m.s.n.m. al nivel taxonómico de géneros en dos áreas geográfi cas y surelación con factores espaciales, climáticos y históricos. Las áreas defi nidas fueron:1 Colombia, la cual se defi ne para los sitios en este país localizados alrededor delEcuador geográfi co; y 2 Neotrópico: sitios externos a Colombia más distantesdel Ecuador geográfi co. Las preguntas a responder fueron: ¿Qué tan comparablesson las tasas de recambio fl orístico de géneros en las diferentes áreas geográfi cas?y ¿Qué tan similares son los factores que controlan la distribución de géneros?La diversidad beta fue diferente según el área geográfi ca. La variación climática,representada por la precipitación, fue más relevante a escala del neotrópico, mientrasque la variación altitudinal lo fue a escala de Colombia. Los patrones de distribuciónal nivel de género, fueron poco congruentes con los reportados a nivel de especiesen bosques montanos del neotrópico, especialmente cuando se consideraron datoscercanos alrededor del Ecuador geográfi co en Colombia.

Lahar—River of volcanic mud and debris

Science.gov (United States)

Major, Jon J.; Pierson, Thomas C.; Vallance, James W.

2018-05-09

Lahar, an Indonesian word for volcanic mudflow, is a mixture of water, mud, and volcanic rock flowing swiftly along a channel draining a volcano. Lahars can form during or after eruptions, or even during periods of inactivity. They are among the greatest threats volcanoes pose to people and property. Lahars can occur with little to no warning, and may travel great distances at high speeds, destroying or burying everything in their paths.Lahars form in many ways. They commonly occur when eruptions melt snow and ice on snow-clad volcanoes; when rains fall on steep slopes covered with fresh volcanic ash; when crater lakes, volcano glaciers or lakes dammed by volcanic debris suddenly release water; and when volcanic landslides evolve into flowing debris. Lahars are especially likely to occur at erupting or recently active volcanoes.Because lahars are so hazardous, U.S. Geological Survey scientists pay them close attention. They study lahar deposits and limits of inundation, model flow behavior, develop lahar-hazard maps, and work with community leaders and governmental authorities to help them understand and minimize the risks of devastating lahars.

Volcanic styles at Alba Patera, Mars: implications of lava flow morphology to the volcanic history

International Nuclear Information System (INIS)

Schneeberger, D.M.; Pieri, D.C.

1988-01-01

Alba Patera presents styles of volcanism that are unique to Mars. Its very low profile, large areal extent, unusually long and voluminous lava flows, and circumferential graben make it among Mars' most interesting volcanic features. Clues to Alba's volcanic history are preserved in its morphology and stratigraphy. Understanding the relationship of lava flow morphology to emplacement processes should enable estimates of viscosity, effusion rate, and gross composition to be made. Lava flows, with dimensions considered enormous by terrestrial standards, account for a major portion of the exposed surface of Alba Patera. These flows exhibit a range of morphologies. While most previous works have focused on the planimetric characteristics, attention was drawn to the important morphological attributes, paying particular attention to what the features suggest about the emplacement process

El rol del desempeño típico y máximo en selección de personal

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UTE CHRISTINE KLEHE

2007-01-01

Full Text Available Este artículo presenta una revisión de la investigación sobre la distinción entre desempeño típico y máximo. Comenzando con una distinción entre lo que los solicitantes pueden hacer (desempeño máximo y lo que ellos harán (desempeño típico, en términos de su desempeño probable en el puesto, demostraremos cómo tal distinción puede añadir información valiosa tanto para profesionales como para investigadores en selección de personal. Mientras que la distinción entre desempeño típico y máximo se ajusta bien a los actuales modelos de desempeño laboral y ha recibido considerable atención en contextos teóricos, suele ser pasada por alto tanto por investigadores como por profesionales en selección de personal. Los investigadores realizan extensos estudios de validación y las organizaciones hacen grandes inversiones financieras en la selección de nuevos empleados sin saber cuál de estos dos aspectos del rendimiento están prediciendo o están intentando predecir. Finalmente, propondremos algunas áreas para futura investigación en el estudio del desempeño típico y máximo.

Through the Microscope: Understanding "The Tempest" in the Context of the Introduction to Pico della Mirandola’s "Oration on the Dignity of Man"

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Michaela Krämer

2016-12-01

Full Text Available In the format of interpretation the creative laboratory of Shakespeare’s “The Tempest” is being revealed. By all accounts “The Tempest” has no specific sources. This study, however, supposes, that Shakespeare could refer to the basic concept and, from this perspective, even very closely rely on the details. Hence, it is proved, that the philosophical impulse of Shakespeare’s tragedy can be considered the introduction to the “Oration on the Dignity of Man” by Giovanni Pico della Mirandola, created for the forbidden later theological discussions on relevant topics in Rome (1486, which dealt with the possibility of moral self-determination and individual responsibility. Imposing the lines of the treatise by Pico on the images and plot of the drama by Shakespeare, we immediately notice a twisted three-dimensional image, the transition from abstract relationship to the visible processes of existence and consciousness, at the same time fantastic and real. This analysis is based on the statement, that “The Tempest” can be interpreted as the staging of memorable images of Pico. This statement is relevant to point of view, according to which Shakespeare could choose the idea of the Oration, or directly from the passage of the text. Shakespeare consciously goes beyond the ideas of Pico. If the quotations from the text of Pico are considered as a subtext, it immediately becomes evident that scene, characters and action of the play are based in some way on a complex conceptual scheme. With the underlying meaning of the Oration by Pico, “The Tempest” is a powerful creative experiment and a reasonable appeal to the uniqueness of human life and spiritual freedom of a man. Thus, this study, without resorting to discuss specific aspects of the play, aspires to promote scientific debate about its hidden meaning.

Imaging volcanic CO2 and SO2

Science.gov (United States)

Gabrieli, A.; Wright, R.; Lucey, P. G.; Porter, J. N.

2017-12-01

Detecting and quantifying volcanic carbon dioxide (CO2) and sulfur dioxide (SO2) emissions is of relevance to volcanologists. Changes in the amount and composition of gases that volcanoes emit are related to subsurface magma movements and the probability of eruptions. Volcanic gases and related acidic aerosols are also an important atmospheric pollution source that create environmental health hazards for people, animals, plants, and infrastructures. For these reasons, it is important to measure emissions from volcanic plumes during both day and night. We present image measurements of the volcanic plume at Kīlauea volcano, HI, and flux derivation, using a newly developed 8-14 um hyperspectral imaging spectrometer, the Thermal Hyperspectral Imager (THI). THI is capable of acquiring images of the scene it views from which spectra can be derived from each pixel. Each spectrum contains 50 wavelength samples between 8 and 14 um where CO2 and SO2 volcanic gases have diagnostic absorption/emission features respectively at 8.6 and 14 um. Plume radiance measurements were carried out both during the day and the night by using both the lava lake in the Halema'uma'u crater as a hot source and the sky as a cold background to detect respectively the spectral signatures of volcanic CO2 and SO2 gases. CO2 and SO2 path-concentrations were then obtained from the spectral radiance measurements using a new Partial Least Squares Regression (PLSR)-based inversion algorithm, which was developed as part of this project. Volcanic emission fluxes were determined by combining the path measurements with wind observations, derived directly from the images. Several hours long time-series of volcanic emission fluxes will be presented and the SO2 conversion rates into aerosols will be discussed. The new imaging and inversion technique, discussed here, are novel allowing for continuous CO2 and SO2 plume mapping during both day and night.

Abordajes endoscópicos a la base de cráneo anterior

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Gonzalo De Los Santos

2016-07-01

Full Text Available Los abordajes endoscópicos a la base de cráneo anterior se han desarrollado de forma muy importante en las últimas décadas y continúan extendiéndose paralelamente a la aparición de nuevo instrumental y equipo que facilitan su aplicación. Factores importantes que han contribuido a ello son la posibilidad de acceder de forma directa a zonas difíciles y la disminución de morbilidad que pueden aportar, manteniendo los resultados esperados. Pero también tienen desventajas y limitaciones pues requieren conocimiento anatómico y el uso de material específico en un campo quirúrgico limitado por el espacio, estructuras anatómicas vitales y la visión bidimensional. La correcta planificación quirúrgica y la selección de los pacientes son elementos fundamentales. Esto nos permitirá determinar si es posible este tipo de abordaje, conocer la localización de la lesión, la zona de entrada al cráneo y el corredor que deberemos utilizar para ello. Los abordajes endoscópicos, correctamente indicados y planificados son procedimientos seguros y efectivos.

Inside the volcanic boiler room: knowledge exchange among stakeholders of volcanic unrest

Science.gov (United States)

Gottsmann, Joachim; Christie, Ryerson; Bretton, Richard

2014-05-01

The knowledge of the causative links between subsurface processes, resulting monitoring signals and imminent eruption is incomplete. As a consequence, hazard assessment and risk mitigation strategies are subject to uncertainty. Discussion of unrest and pre-eruptive scenarios with uncertain outcomes are central during the discourse between a variety of stakeholders in volcanic unrest including scientists, emergency managers, policy makers and the public. Drawing from research within the EC FP7 VUELCO project, we argue that knowledge exchange amongst the different stakeholders of volcanic unrest evolves along three dimensions: 1) the identification of knowledge holders (including local communities) and their needs and expectations, 2) vehicles of communication and 3) trust. In preparing products that feed into risk assessment and management, scientists need to ensure that their deliverables are timely, accurate, clear, understandable and cater to the expectations of emergency managers. The means and content of communication amongst stakeholders need to be defined and adhered to. Finally, efficient and effective interaction between stakeholders is ideally based on mutual trust between those that generate knowledge and those that receive knowledge. For scientists, this entails contextualising volcanic hazard and risk in the framework of environmental and social values. Periods of volcanic quiescence are ideally suited to test established protocols of engagement between stakeholders in preparation for crises situations. The different roles of stakeholders and associated rules of engagement can be scrutinised and reviewed in antecessum rather than ad-hoc during a crisis situation to avoid issues related to distrust, loss of credibility and overall poor risk management. We will discuss these themes drawing from exploitation of research results from Mexico and Ecuador.

Ages of plains volcanism on Mars

Science.gov (United States)

Hauber, Ernst; Jagert, Felix; Broz, Petr

2010-05-01

Plain-style volcanism [1] is widespread in the Tharsis and Elysium volcanic provinces on Mars, [2,3]. Detailed images and topographic data reveal the morphology and topography of clusters of low shields and associated lava flows. The landforms of plains volcanism on Mars have all well-known terrestrial analogues in basaltic volcanic regions, such as Hawaii, Iceland, and in particular the Snake River Plains [4]. The very gentle flank slopes (J. (1981) Icarus, 45, 586-601. [3] Hodges C.A. and Moore H.J. (1994) Atlas of volcanic features on Mars: USGS Prof. Paper 1534, 194 p. [4] Hauber E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 69-95. [5] Wilson L. et al. (2009) J. Volcanol. Geotherm. Res. 185, 28-46. [6] Vaucher, J. et al. (2009) Icarus 204, 418-442. [7] Baratoux D. et al. (2009) J. Volcanol. Geotherm. Res. 185, 47-68. [8] Bleacher J.E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 96-102. [9] Ivanov B.A. (2001) Space Sci. Rev. 96, 87-104. [10] Hartmann W.H. and Neukum G. (2001) Space Sci. Rev. 96, 165-194 [11] Kneissl T. et al. (2010) LPS XVI, submitted. [12] Michael, G.G. and Neukum G. (2010) Earth Planet. Sci. Lett., in press. . [13] Malin M.C. et al. (2007) JGR 112, E05S04, doi: 10.1029/2006JE002808.

Field-trip guide to mafic volcanism of the Cascade Range in Central Oregon—A volcanic, tectonic, hydrologic, and geomorphic journey

Science.gov (United States)

Deligne, Natalia I.; Mckay, Daniele; Conrey, Richard M.; Grant, Gordon E.; Johnson, Emily R.; O'Connor, Jim; Sweeney, Kristin

2017-08-16

The Cascade Range in central Oregon has been shaped by tectonics, volcanism, and hydrology, as well as geomorphic forces that include glaciations. As a result of the rich interplay between these forces, mafic volcanism here can have surprising manifestations, which include relatively large tephra footprints and extensive lava flows, as well as water shortages, transportation and agricultural disruption, and forest fires. Although the focus of this multidisciplinary field trip will be on mafic volcanism, we will also look at the hydrology, geomorphology, and ecology of the area, and we will examine how these elements both influence and are influenced by mafic volcanism. We will see mafic volcanic rocks at the Sand Mountain volcanic field and in the Santiam Pass area, at McKenzie Pass, and in the southern Bend region. In addition, this field trip will occur during a total solar eclipse, the first one visible in the United States in more than 25 years (and the first seen in the conterminous United States in more than 37 years).The Cascade Range is the result of subduction of the Juan de Fuca plate underneath the North American plate. This north-south-trending volcanic mountain range is immediately downwind of the Pacific Ocean, a huge source of moisture. As moisture is blown eastward from the Pacific on prevailing winds, it encounters the Cascade Range in Oregon, and the resulting orographic lift and corresponding rain shadow is one of the strongest precipitation gradients in the conterminous United States. We will see how the products of the volcanoes in the central Oregon Cascades have had a profound influence on groundwater flow and, thus, on the distribution of Pacific moisture. We will also see the influence that mafic volcanism has had on landscape evolution, vegetation development, and general hydrology.

"Arrancale los dientes al trópico": ambiente,enfermedad y el programa sanitario de Estados Unidos en Panamá, 1904-1914

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Paul Sutter

2000-01-01

Full Text Available Apoyado en fuentes escritas durante y después de la construcción del Canal de Panamá (1904- 1914, este artículo examina la forma en que los estadunidenses conceptualizaron los trópicos de Panamá y el modo en que dicha conceptualización orientó su política, en especial la sanitaria, durante el periodo de construcción del canal. Debido a que las enfermedades tropicales, en especial la malaria y la fiebre amarilla, ocupaban un lugar central en el modo de concebir los trópicos por parte de los estadunidenses, el objetivo de este trabajo es mostrar que los problemas de enfermedades en Panamá eran el resultado de complejas interacciones ambientales y sociales, y no una mera característica natural de los trópicos.

La industria metálica del depósito sepulcral de Pico Ramos (Muskiz, Biscay.

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José Mª Salgado

1995-01-01

Full Text Available Los materiales metálicos del conjunto calcolítico de la cueva sepulcral de Pico Ramos son un punzón biapuntado y una punta de cobre. Además, existe una pieza laminar que podría pertenecer a este momento a pesar de que cuenta con impurezas más frecuentes en épocas posteriores. El análisis de Fluorescencia de Rayos X de las dos primeras piezas citadas indica que ambas cuentan con un   contenido similar de cobre, bajo en níquel y alto en arsénico, en comparación con otros materiales del País Vasco. Se apunta la posibilidad de que el material de Pico Ramos corresponda a una primera fase de la metalurgia, quizá producto de intercambios previos al desarrollo local del proceso productivo metalúrgico.

Long term volcanic hazard analysis in the Canary Islands

Science.gov (United States)

Becerril, L.; Galindo, I.; Laín, L.; Llorente, M.; Mancebo, M. J.

2009-04-01

Historic volcanism in Spain is restricted to the Canary Islands, a volcanic archipelago formed by seven volcanic islands. Several historic eruptions have been registered in the last five hundred years. However, and despite the huge amount of citizens and tourist in the archipelago, only a few volcanic hazard studies have been carried out. These studies are mainly focused in the developing of hazard maps in Lanzarote and Tenerife islands, especially for land use planning. The main handicap for these studies in the Canary Islands is the lack of well reported historical eruptions, but also the lack of data such as geochronological, geochemical or structural. In recent years, the use of Geographical Information Systems (GIS) and the improvement in the volcanic processes modelling has provided an important tool for volcanic hazard assessment. Although this sophisticated programs are really useful they need to be fed by a huge amount of data that sometimes, such in the case of the Canary Islands, are not available. For this reason, the Spanish Geological Survey (IGME) is developing a complete geo-referenced database for long term volcanic analysis in the Canary Islands. The Canarian Volcanic Hazard Database (HADA) is based on a GIS helping to organize and manage volcanic information efficiently. HADA includes the following groups of information: (1) 1:25.000 scale geologic maps, (2) 1:25.000 topographic maps, (3) geochronologic data, (4) geochemical data, (5) structural information, (6) climatic data. Data must pass a quality control before they are included in the database. New data are easily integrated in the database. With the HADA database the IGME has started a systematic organization of the existing data. In the near future, the IGME will generate new information to be included in HADA, such as volcanological maps of the islands, structural information, geochronological data and other information to assess long term volcanic hazard analysis. HADA will permit

Properties of volcanic soils in cold climate conditions

Science.gov (United States)

Kuznetsova, Elena

2017-04-01

Layers of volcanic ash and the Andosol soils derived from them may play an important role in preserving snow and ice as well as developing permafrost conditions in the immediate vicinity of volcanoes of high elevation or those situated at high latitudes, and land areas, often distant from volcanic activity that are either prone to permafrost or covered by snow and ice, but are affected by the deposition of subaerial ash. The special properties of volcanic ash that are responsible are critically reviewed particularly in relation to recent research in Kamchatka in the Far East of Russia. Of particular importance are the thermal properties and the unfrozen water contents of ash layers and the rate at which the weathering of volcanic glass takes place. Volcanic glass is the most easily weathered component of volcanic ejecta (Shoji et al., 1993; Kimble et al., 2000). There are many specific environmental conditions, including paleoclimate and present-day climate, the composition of volcanic tephra and glaciation history, which cause the differences in weathering and development of volcanic ash soils (Zehetner et al., 2003). The preservation of in situ, unweathered, and unaltered surficial ash-fall deposits in the cold regions has important implications for paleoclimate and glacial history. Ash-fall deposits, which trap and preserve the soils, sediments, and landforms on which they fall, can be used to resolve local climate conditions (temperature and moisture) at the ash site during ash-fall deposition. The preservation of detailed sedimentary features (e.g. bedding in the ash, sharpness of stratigraphic contacts) can tell us about their post-depositional history, whether they have been redeposited by wind or water, or overridden by glaciers (Marchant et al., 1996). Weathering of volcanic glass results in the development of amorphous clay minerals (e.g. allophane, opal, palagonite) but this takes place much slower in cold than under warmer climate conditions. Only few

The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians): Eruption chronology and magma type variation

Science.gov (United States)

Molnár, Kata; Harangi, Szabolcs; Lukács, Réka; Dunkl, István; Schmitt, Axel K.; Kiss, Balázs; Garamhegyi, Tamás; Seghedi, Ioan

2018-04-01

Combined zircon U-Th-Pb and (U-Th)/He dating was applied to refine the eruption chronology of the last 2 Myr for the andesitic and dacitic Pilişca volcano and Ciomadul Volcanic Dome Complex (CVDC), the youngest volcanic area of the Carpathian-Pannonian region, located in the southernmost Harghita, eastern-central Europe. The proposed eruption ages, which are supported also by the youngest zircon crystallization ages, are much younger than the previously determined K/Ar ages. By dating every known eruption center in the CVDC, repose times between eruptive events were also accurately determined. Eruption of the andesite at Murgul Mare (1865 ± 87 ka) and dacite of the Pilişca volcanic complex (1640 ± 37 ka) terminated an earlier pulse of volcanic activity within the southernmost Harghita region, west of the Olt valley. This was followed by the onset of the volcanism in the CVDC, which occurred after several 100s kyr of eruptive quiescence. At ca. 1 Ma a significant change in the composition of erupted magma occurred from medium-K calc-alkaline compositions to high-K dacitic (Baba-Laposa dome at 942 ± 65 ka) and shoshonitic magmas (Malnaş and Bixad domes; 964 ± 46 ka and 907 ± 66 ka, respectively). Noteworthy, eruptions of magmas with distinct chemical compositions occurred within a restricted area, a few km from one another. These oldest lava domes of the CVDC form a NNE-SSW striking tectonic lineament along the Olt valley. Following a brief (ca. 100 kyr) hiatus, extrusion of high-K andesitic magma continued at Dealul Mare (842 ± 53 ka). After another ca. 200 kyr period of quiescence two high-K dacitic lava domes extruded (Puturosul: 642 ± 44 ka and Balvanyos: 583 ± 30 ka). The Turnul Apor lava extrusion occurred after a ca. 200 kyr repose time (at 344 ± 33 ka), whereas formation of the Haramul Mic lava dome (154 ± 16 ka) represents the onset of the development of the prominent Ciomadul volcano. The accurate determination of eruption dates shows that the

Multi-wavelength speckle reduction for laser pico-projectors using diffractive optics

Science.gov (United States)

Thomas, Weston H.

Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser's stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a

Dislipidemias e antipsicóticos atípicos Dyslipidemias and atypical antipsychotics

Directory of Open Access Journals (Sweden)

Edilberto Amorim de Cerqueira Filho

2006-01-01

Full Text Available OBJETIVO: Um progressivo número de evidências surge associando o uso de antipsicóticos atípicos a dislipidemias, situação pouco atentada por considerável número de psiquiatras e preditora importante de doenças cardiovasculares (DCVs e de morbimortalidade. O propósito deste estudo é revisar a associação entre o uso de antipsicóticos atípicos e o desenvolvimento de dislipidemias em pacientes com esquizofrenia. MÉTODOS: A pesquisa bibliográfica utilizou os bancos de dados MEDLINE e Scientific Electronic Library Online (SciELO, com os descritores: schizophrenia, dyslipidemia, hyperlipidemia e lipids, para identificar artigos originais publicados no período de 1997 a setembro de 2006. RESULTADOS: Os artigos foram agrupados segundo cada agente terapêutico, de acordo com o seu impacto sobre o perfil lipídico. CONCLUSÃO: Observa-se maior risco de desenvolvimento de dislipidemias em pacientes com esquizofrenia em uso de alguns antipsicóticos atípicos. Intervenções comportamentais e farmacológicas devem ser associadas nos indivíduos com esquizofrenia em tratamento antipsicótico e que desenvolvem dislipidemias.OBJECTIVE: Pieces of evidence appear associating the use of atypical antipsychotics to dyslipidemias, situation that is of little attention by considerable number of psychiatrists and important predictor of cardiovascular illnesses and morbi-mortality. The intention of this study is to review the association between the atypical antipsychotic use and the development of dyslipidemias in patients with schizophrenia. METHODS: The bibliographical research used databases MEDLINE and SciELO, for the key words: schizophrenia, dyslipidemia, hyperlipidemia and lipids, with the objective to identify original articles published in the period of 1997 to September 2006. RESULTS: The articles were distributed according to each therapeutic agent and their impact on lipidic profile. CONCLUSION: Higher risk of development of dyslipidemias

Developing International Guidelines on Volcanic Hazard Assessments for Nuclear Facilities

Science.gov (United States)

Connor, Charles

2014-05-01

Worldwide, tremendous progress has been made in recent decades in forecasting volcanic events, such as episodes of volcanic unrest, eruptions, and the potential impacts of eruptions. Generally these forecasts are divided into two categories. Short-term forecasts are prepared in response to unrest at volcanoes, rely on geophysical monitoring and related observations, and have the goal of forecasting events on timescales of hours to weeks to provide time for evacuation of people, shutdown of facilities, and implementation of related safety measures. Long-term forecasts are prepared to better understand the potential impacts of volcanism in the future and to plan for potential volcanic activity. Long-term forecasts are particularly useful to better understand and communicate the potential consequences of volcanic events for populated areas around volcanoes and for siting critical infrastructure, such as nuclear facilities. Recent work by an international team, through the auspices of the International Atomic Energy Agency, has focused on developing guidelines for long-term volcanic hazard assessments. These guidelines have now been implemented for hazard assessment for nuclear facilities in nations including Indonesia, the Philippines, Armenia, Chile, and the United States. One any time scale, all volcanic hazard assessments rely on a geologically reasonable conceptual model of volcanism. Such conceptual models are usually built upon years or decades of geological studies of specific volcanic systems, analogous systems, and development of a process-level understanding of volcanic activity. Conceptual models are used to bound potential rates of volcanic activity, potential magnitudes of eruptions, and to understand temporal and spatial trends in volcanic activity. It is these conceptual models that provide essential justification for assumptions made in statistical model development and the application of numerical models to generate quantitative forecasts. It is a

Basaltic volcanic episodes of the Yucca Mountain region

International Nuclear Information System (INIS)

Crowe, B.M.

1990-01-01

The purpose of this paper is to summarize briefly the distribution and geologic characteristics of basaltic volcanism in the Yucca Mountain region during the last 10--12 Ma. This interval largely postdates the major period of silicic volcanism and coincides with and postdates the timing of major extensional faulting in the region. Field and geochronologic data for the basaltic rocks define two distinct episodes. The patterns in the volume and spatial distribution of these basaltic volcanic episodes in the central and southern part of the SNVF are used as a basis for forecasting potential future volcanic activity in vicinity of Yucca Mountain. 33 refs., 2 figs

Monogenetic volcanism: personal views and discussion

Science.gov (United States)

Németh, K.; Kereszturi, G.

2015-11-01

Monogenetic volcanism produces small-volume volcanoes with a wide range of eruptive styles, lithological features and geomorphic architectures. They are classified as spatter cones, scoria (or cinder) cones, tuff rings, maars (maar-diatremes) and tuff cones based on the magma/water ratio, dominant eruption styles and their typical surface morphotypes. The common interplay between internal, such as the physical-chemical characteristics of magma, and external parameters, such as groundwater flow, substrate characteristics or topography, plays an important role in creating small-volume volcanoes with diverse architectures, which can give the impression of complexity and of similarities to large-volume polygenetic volcanoes. In spite of this volcanic facies complexity, we defend the term "monogenetic volcano" and highlight the term's value, especially to express volcano morphotypes. This study defines a monogenetic volcano, a volcanic edifice with a small cumulative volume (typically ≤1 km3) that has been built up by one continuous, or many discontinuous, small eruptions fed from one or multiple magma batches. This definition provides a reasonable explanation of the recently recognized chemical diversities of this type of volcanism.

The Elusive Evidence of Volcanic Lightning.

Science.gov (United States)

Genareau, K; Gharghabi, P; Gafford, J; Mazzola, M

2017-11-14

Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current. The melted ash is simultaneously expelled from the channel by the heated, expanding air, permitting particles to cool during atmospheric transport before coming to rest in ash fall deposits. The limited size of this ideal melting zone explains the low number of LIVS typically observed in volcanic ash despite the frequent occurrence of lightning during explosive eruptions.

Tópicos generales de planeación estratégica

OpenAIRE

Rosenstiehl-Martínez, José Luis

2017-01-01

El presente documento está dirigido a los estudiantes de administración de empresas y carreras afines, tiene como objetivo presentar una guía para el desarrollo del Curso de Planeación Estratégica, orientado a describir los tópicos generales de la planeación estratégica como herramienta de consulta para los estudiantes. Para este se consultaron autores que han teorizado sobre la temática de planeación como función esencial del proceso administrativo. Contiene dos unidades en las que se realiz...

Los productos típicos y su reglamentación.

OpenAIRE

Cartay, Rafael

2003-01-01

1.- Artículos Cartay, Rafael. "Los productos típicos y su reglamentación. Una tentativa de aplicación de la denominación de origen al cacao venezolano" Kalvatchev, Zlatko; Garzaro, Domingo; Guerra Cedezo, Franklin. "Theobroma Cacao L.: Un nuevo enfoque para nutrición y salud" Anido, Daniel; Gutiérrez, Alejandro. "La demanda de las calorías en Venezuela 1970-1995: Algunas evidencias empíricas" Molina, Luisa Elena. "Notas sobre la situación de la producción primaria de arroz en Ven...

Principal geological characteristics of the volcanic-type uranium deposits in China

International Nuclear Information System (INIS)

Fang Xiheng

2009-01-01

The volcanic-type uranium deposits in China distribute in two gigantic active belts, that is, circum-Pacific belt and latitudinal structure belt crossing Europe-Asia. The volcanic-type uranium deposits occur in continental volcanics,which are mainly composed of acid or alkali volcanics. Based on the study of 87 Sr/ 86 Sr initial ratio, REE distribution pattern and melt inclusion thermometry of volcanics, it is found that volcanic magma originated mainly from high-temperature melt of sialsphere and they were propably contaiminated partially by mantle materials. The volcanic eruption was controlled by regional fault and formed eruption belt, the beld can be divided into several sub-belt which was comprised by a serial eruption centres. The volcanic-type uranium deposits occur by the side of down-faulted red basin or associated with basic swarm. This means that the uranium mineralization is related to deep tectonics-magmatism. The paper proposes that the moderate erosion of volcanic belt is an important precondition to find uranium deposits. (authors)

Eocene volcanism and the origin of horizon A

Science.gov (United States)

Gibson, T.G.; Towe, K.M.

1971-01-01

A series of closely time-equivalent deposits that correlate with seismic reflector horizon A exists along the coast of eastern North America. These sediments of Late-Early to Early-Middle Eocene age contain an authigenic mineral suite indicative of the alteration of volcanic glass. A volcanic origin for these siliceous deposits onshore is consistent with a volcanic origin for the cherts of horizon A offshore.

Local and remote infrasound from explosive volcanism

Science.gov (United States)

Matoza, R. S.; Fee, D.; LE Pichon, A.

2014-12-01

Explosive volcanic eruptions can inject large volumes of ash into heavily travelled air corridors and thus pose a significant societal and economic hazard. In remote volcanic regions, satellite data are sometimes the only technology available to observe volcanic eruptions and constrain ash-release parameters for aviation safety. Infrasound (acoustic waves ~0.01-20 Hz) data fill this critical observational gap, providing ground-based data for remote volcanic eruptions. Explosive volcanic eruptions are among the most powerful sources of infrasound observed on earth, with recordings routinely made at ranges of hundreds to thousands of kilometers. Advances in infrasound technology and the efficient propagation of infrasound in the atmosphere therefore greatly enhance our ability to monitor volcanoes in remote regions such as the North Pacific Ocean. Infrasound data can be exploited to detect, locate, and provide detailed chronologies of the timing of explosive volcanic eruptions for use in ash transport and dispersal models. We highlight results from case studies of multiple eruptions recorded by the International Monitoring System and dedicated regional infrasound networks (2008 Kasatochi, Alaska, USA; 2008 Okmok, Alaska, USA; 2009 Sarychev Peak, Kuriles, Russian Federation; 2010 Eyjafjallajökull, Icleand) and show how infrasound is currently used in volcano monitoring. We also present progress towards characterizing and modeling the variability in source mechanisms of infrasound from explosive eruptions using dedicated local infrasound field deployments at volcanoes Karymsky, Russian Federation and Sakurajima, Japan.

Developing Atmospheric Science Tools for Teachers Based on Research at the Pico Mountain Observatory, Pico Island, Azores

Science.gov (United States)

Harkness, L.; Mazzoleni, L. R.; Dzepina, K.; Mazzoleni, C.; China, S.

2013-12-01

Atmospheric science and climate change are becoming increasingly important, especially in education, as the Next Generation Science Standards now include climate change. A collaborating team of research scientists and students are studying the free troposphere, specifically the aerosol composition and properties, on the island of Pico in the Azores Archipelago. The research station sits in the caldera of Mount Pico, 2225 meters above sea level. At this elevation, the station is above the marine boundary layer, thus placing it in the free troposphere. In this work, collaboration between a high school Earth Science teacher and university researchers was formed with the goal of developing classroom and outreach materials regarding atmospheric science. Among the materials, a video was created containing: site and project background, explanation of some of the instruments used and candid conversations regarding science and research. The video serves several purposes, such as informing students and the general public about what is happening in the atmosphere and informing students about the importance of science and research. The video could also be used to educate the local island community and tourists. Other materials designed include data directly obtained from the project, such as measurements of aerosol particles in electron microscopy photos (which were imaged for particle morphology and size), and composition of the aerosol particles. Students can use this evidence, as well as other data, to gain a better understanding of aerosols and the overall effect they have on the climate. Students will discover this evidence as they work through a series of experiments and activities. Using the strategy of Claim-Evidence-Reasoning as a way to answer scientific questions, students will use the evidence they gathered to explain their ideas. One such question could be, 'How do aerosols affect the climate?' and the student's 'claim' is their answer to that question. In the

Volcanism Studies: Final Report for the Yucca Mountain Project

Energy Technology Data Exchange (ETDEWEB)

Bruce M. Crowe; Frank V. Perry; Greg A. Valentine; Lynn M. Bowker

1998-12-01

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. An assessment of the risk of future volcanic activity is one of many site characterization studies that must be completed to evaluate the Yucca Mountain site for potential long-term storage of high-level radioactive waste. The presence of several basaltic volcanic centers in the Yucca Mountain region of Pliocene and Quaternary age indicates that there is a finite risk of a future volcanic event occurring during the 10,000-year isolation period of a potential repository. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt (<5 Ma). The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. The age of the Lathrop Wells center is now confidently determined to be about 75 thousand years old. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. The Crater Flat volcanic zone is

Pico-ampere current sensitivity and CdSe quantum dots assembly assisted charge transport in ferroelectric liquid crystal

Science.gov (United States)

Pratap Singh, Dharmendra; Boussoualem, Yahia; Duponchel, Benoit; Sahraoui, Abdelhak Hadj; Kumar, Sandeep; Manohar, Rajiv; Daoudi, Abdelylah

2017-08-01

Octadecylamine capped CdSe quantum dots (QDs) dispersed 4-(1-methyl-heptyloxy)-benzoic acid 4‧-octyloxy-biphenyl-4-yl ester ferroelectric liquid crystal (FLC) were deposited over gold coated quartz substrate using dip-coating. The topographical investigation discloses that the homogeneously dispersed QDs adopt face-on to edge-on assembly in FLC matrix owing to their concentration. Current-voltage (I-V) measurement was performed using conductive atomic force microscopy (CAFM) which yields ohmic to critical diode like I-V curves depending upon the concentration of QDs in FLC. The recorded pico-ampere (pA) current sensitivity in FLC-QDs composites is attributed to micro-second drift time of electron due to weak electronic coupling between the π-electrons on the FLC and s-electrons on the metal surface. The observed pico-ampere sensitivity is the least current sensitivity recorded so far. For FLC-QDs composites, almost 24% faster electro-optic response was observed in comparison to pure FLC. The pico-ampere current sensitivity can be utilized in touch screen displays whereas the change in polarization for low applied electric field ameliorates the increased electrical susceptibility counteracting the internal electric field and its use in electronic data storage and faster electro-optical devices.

Cenozoic volcanic rocks of Saudi Arabia

Science.gov (United States)

Coleman, R.G.; Gregory, R.T.; Brown, G.F.

2016-01-01

The Cenozoic volcanic rocks of Saudi Arabia cover about 90,000 km2, one of the largest areas of alkali olivine basalt in the world. These volcanic rocks are in 13 separate fields near the eastern coast of the Red Sea and in the western Arabian Peninsula highlands from Syria southward to the Yemen Arab Republic.

Microphysical Properties of Alaskan Volcanic Ash

Science.gov (United States)

Puthukkudy, A.; Espinosa, R.; Rocha Lima, A.; Remer, L.; Colarco, P. R.; Whelley, P.; Krotkov, N. A.; Young, K.; Dubovik, O.; Wallace, K.; Martins, J. V.

2017-12-01

Volcanic ash has the potential to cause a variety of severe problems for human health and the environment. Therefore, effective monitoring of the dispersion and fallout from volcanic ash clouds and characterization of the aerosol particle properties are essential. One way to acquire information from volcanic clouds is through satellite remote sensing: such images have greater coverage than ground-based observations and can present a "big picture" perspective. A challenge of remote sensing is that assumptions of certain properties of the target are often a pre-requisite for making accurate and quantitative retrievals. For example, detailed information about size distribution, sphericity, and optical properties of the constituent matter is needed or must be assumed. The same kind of information is also needed for atmospheric transport models to properly simulate the dispersion and fallout of volcanic ash. Presented here is a laboratory method to determine the microphysical and optical properties of volcanic ash samples collected from two Alaskan volcanoes with markedly different compositions. Our method uses a Polarized Imaging Nephelometer (PI-Neph) and a system that re-suspends the particles in an air flow. The PI-Neph measures angular light scattering and polarization of the re-suspended particles from 3o to 175o in scattering angle, with an angular resolution of 1o . Primary measurements include phase function and polarized phase function at three wavelengths (445nm, 532nm, and 661nm). Size distribution, sphericity, and complex refractive index are retrieved indirectly from the PI-Neph measurements using the GRASP (Generalized Retrieval of Aerosol and Surface Properties) inversion algorithm. We report the results of this method applied to samples from the Mt. Okmok (2008) and Mt. Katmai (1912) volcanic eruptions. To our knowledge, this is the first time direct measurements of phase matrix elements of ash from Mt. Okmok and Mt. Katmai have been reported. Retrieved

Volcanic hazard studies for the Yucca Mountain project

International Nuclear Information System (INIS)

Crowe, B.; Turrin, B.; Wells, S.; Perry, F.; McFadden, L.; Renault, C.E.; Champion, D.; Harrington, C.

1989-01-01

Volcanic hazard studies are ongoing to evaluate the risk of future volcanism with respect to siting of a repository for disposal of high-level radioactive waste at the Yucca Mountain site. Seven Quaternary basaltic volcanic centers are located a minimum distance of 12 km and a maximum distance of 47 km from the outer boundary of the exploration block. The conditional probability of disruption of a repository by future basaltic volcanism is bounded by the range of 10/sup /minus/8/ to 10/sup /minus/10/ yr/sup /minus/1/. These values are currently being reexamined based on new developments in the understanding of the evaluation of small volume, basaltic volcanic centers including: (1) Many, perhaps most, of the volcanic centers exhibit brief periods of eruptive activity separated by longer periods of inactivity. (2) The centers may be active for time spans exceeding 10 5 yrs, (3) There is a decline in the volume of eruptions of the centers through time, and (4) Small volume eruptions occurred at two of the Quaternary centers during latest Pleistocene or Holocene time. We classify the basalt centers as polycyclic, and distinguish them from polygenetic volcanoes. Polycyclic volcanism is characterized by small volume, episodic eruptions of magma of uniform composition over time spans of 10 3 to 10 5 yrs. Magma eruption rates are low and the time between eruptions exceeds the cooling time of the magma volumes. 25 refs., 2 figs

Volcanic eruption plumes on Io

International Nuclear Information System (INIS)

Strom, R.G.; Terrile, R.J.; Masursky, H.; Hansen, C.

1979-01-01

The detection of an umbrella-shaped plume extending about 280 km above the bright limb of Io was one of the most important discoveries made during the Voyager 1 encounter with the jovian system. This discovery proves that Io is volcanically active at present, and the number and magnitude of these eruptions indicate that Io is the most volcanically active body so far discovered in the Solar System. Preliminary analyses of these eruptive plumes are presented. (U.K.)

Volcanic hazards and aviation safety

Science.gov (United States)

Casadevall, Thomas J.; Thompson, Theodore B.; Ewert, John W.; ,

1996-01-01

An aeronautical chart was developed to determine the relative proximity of volcanoes or ash clouds to the airports and flight corridors that may be affected by volcanic debris. The map aims to inform and increase awareness about the close spatial relationship between volcanoes and aviation operations. It shows the locations of the active volcanoes together with selected aeronautical navigation aids and great-circle routes. The map mitigates the threat that volcanic hazards pose to aircraft and improves aviation safety.

Improving volcanic ash forecasts with ensemble-based data assimilation

NARCIS (Netherlands)

Fu, Guangliang

2017-01-01

The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash forecasting in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be

The Lathrop Wells volcanic center

International Nuclear Information System (INIS)

Crowe, B.; Morley, R.

1992-01-01

The Lathrop Wells volcanic center is located 20 km south of the potential Yucca Mountain site, at the south end of the Yucca Mountain range. This paper discusses a detailed Study Plan which was prepared describing planned geochronology and field studies to assess the chronology of the Lathrop Wells volcanic center and other Quaternary volcanic centers in the region. A paper was published discussing the geomorphic and soil evidence for a late Pleistocene or Holoceno age for the main cone of the center. The purpose of this paper was to expose the ideas concerning the age of the Lathrop Wells center to scientific scrutiny. Additionally, field evidence was described suggesting the Lathrop Wells center may have formed from multiple eruptive events with significant intervals of no activity between events. This interpretation breaks with established convention in the volcanological literature that small volume basalt centers are monogenetic

Major-element geochemistry of the Silent Canyon--Black Mountain peralkaline volcanic centers, northwestern Nevada Test Site: applications to an assessment of renewed volcanism

International Nuclear Information System (INIS)

Crowe, B.M.; Sargent, K.A.

1979-01-01

The Silent Canyon and Black Mountain volcanic centers are located in the northern part of the Nevada Test Site. The Silent Canyon volcanic center is a buried cauldron complex of Miocene age (13 to 15 m.y.). Black Mountain volcanic center is an elliptical-shaped cauldron complex of late Miocene age. The lavas and tuffs of the two centers comprise a subalkaline-peralkaline association. Rock types range from quartz normative subalkaline trachyte and rhyolite to peralkaline commendite. The Gold Flat Member of the Thirsty Canyon Tuff (Black Mountain) is a pantellerite. The major-element geochemistry of the Black Mountain--Silent Canyon volcanic centers differ in the total range and distribution of SiO 2 , contents, the degree of peralkalinity (molecular Na 2 O + K 2 O > Al 2 O 3 ) and in the values of total iron and alumina through the range of rock types. These differences indicate that the suites were unrelated and evolved from differing magma bodies. The Black Mountain volcanic cycle represents a renewed phase of volcanism following cessation of the Timber Mountain--Silent Canyon volcanic cycles. Consequently, there is a small but numerically incalculable probability of recurrence of Black Mountain-type volcanism within the Nevada Test Site region. This represents a potential risk with respect to deep geologic storage of high-level radioactive waste at the Nevada Test Site

ULTRASONIDO ENDOSCÓPICO EN PATOLOGÍAS DEL PÁNCREAS

OpenAIRE

LÁZARO ANTONIO ARANGO M., DR.; CLAUDIA PATRICIA DÍAZ T., DRA.

2015-01-01

El ultrasonido endoscópico (EUS) ha revolucionado el diagnóstico y el manejo de muchas patologías de la vía digestiva, particularmente la patología pancreática, convirtiéndose en un examen prácticamente imprescindible en el abordaje diagnóstico y terapéutico de un paciente con un problema de páncreas. Es necesario dejar en claro que el método no es único y que para lograr una sensibilidad alta y cumplir el objetivo de realizar lo más adecuado, debe sumarse a otros métodos de acuerdo a cada...

Ash production by attrition in volcanic conduits and plumes.

Science.gov (United States)

Jones, T J; Russell, J K

2017-07-17

Tephra deposits result from explosive volcanic eruption and serve as indirect probes into fragmentation processes operating in subsurface volcanic conduits. Primary magmatic fragmentation creates a population of pyroclasts through volatile-driven decompression during conduit ascent. In this study, we explore the role that secondary fragmentation, specifically attrition, has in transforming primary pyroclasts upon transport in volcanic conduits and plumes. We utilize total grain size distributions from a suite of natural and experimentally produced tephra to show that attrition is likely to occur in all explosive volcanic eruptions. Our experimental results indicate that fine ash production and surface area generation is fast (eruption column stability, tephra dispersal, aggregation, volcanic lightening generation, and has concomitant effects on aviation safety and Earth's climate.

Tellurium in active volcanic environments: Preliminary results

Science.gov (United States)

Milazzo, Silvia; Calabrese, Sergio; D'Alessandro, Walter; Brusca, Lorenzo; Bellomo, Sergio; Parello, Francesco

2014-05-01

Tellurium is a toxic metalloid and, according to the Goldschmidt classification, a chalcophile element. In the last years its commercial importance has considerably increased because of its wide use in solar cells, thermoelectric and electronic devices of the last generation. Despite such large use, scientific knowledge about volcanogenic tellurium is very poor. Few previous authors report result of tellurium concentrations in volcanic plume, among with other trace metals. They recognize this element as volatile, concluding that volcanic gases and sulfur deposits are usually enriched with tellurium. Here, we present some results on tellurium concentrations in volcanic emissions (plume, fumaroles, ash leachates) and in environmental matrices (soils and plants) affected by volcanic emissions and/or deposition. Samples were collected at Etna and Vulcano (Italy), Turrialba (Costa Rica), Miyakejima, Aso, Asama (Japan), Mutnovsky (Kamchatka) at the crater rims by using common filtration techniques for aerosols (polytetrafluoroethylene filters). Filters were both eluted with Millipore water and acid microwave digested, and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Volcanic ashes emitted during explosive events on Etna and Copahue (Argentina) were analyzed for tellurium bulk composition and after leaching experiments to evaluate the soluble fraction of tellurium. Soils and leaves of vegetation were also sampled close to active volcanic vents (Etna, Vulcano, Nisyros, Nyiragongo, Turrialba, Gorely and Masaya) and investigated for tellurium contents. Preliminary results showed very high enrichments of tellurium in volcanic emissions comparing with other volatile elements like mercury, arsenic, thallium and bismuth. This suggests a primary transport in the volatile phase, probably in gaseous form (as also suggested by recent studies) and/or as soluble salts (halides and/or sulfates) adsorbed on the surface of particulate particles and ashes. First

Classifcation of volcanic structure in mesozoic era in the Fuzhou-Shaoxing area

International Nuclear Information System (INIS)

Zhang Fengqi.

1989-01-01

The volcanic structure in the Fuzhou-Shaoxing area can be classified into IV grades: the grade I be the zone of volcanic activity; the grade II be the second zone of volcanic activity; the grade III be the positive, negative volcanic structure; the grade IV be volcanic conduit, volcanic crater, concealed eruption breccia pipe. Based on the geological situation in this area, the different types of volcanic structure are also dealt with. In the mean time, both the embossed type in the depression area and the depressed type in the embossed area in the volcanic basin are pointed out. It is of great advantage to Uranium mineralization

Volcanic eruptions on Io

Science.gov (United States)

Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Hansen, C.; Cook, A. F.

1981-01-01

Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

Improving communication during volcanic crises on small, vulnerable islands

Science.gov (United States)

McGuire, W. J.; Solana, M. C.; Kilburn, C. R. J.; Sanderson, D.

2009-05-01

Increased exposure to volcanic hazard, particularly at vulnerable small islands, is driving an urgent and growing need for improved communication between monitoring scientists, emergency managers and the media, in advance of and during volcanic crises. Information gathering exercises undertaken on volcanic islands (Guadeloupe, St. Vincent and Montserrat) in the Lesser Antilles (eastern Caribbean), which have recently experienced - or are currently experiencing - volcanic action, have provided the basis for the compilation and publication of a handbook on Communication During Volcanic Emergencies, aimed at the principal stakeholder groups. The findings of the on-island surveys point up the critical importance of (1) bringing together monitoring scientists, emergency managers, and representatives of the media, well in advance of a volcanic crisis, and (2), ensuring that procedures and protocols are in place that will allow, as far as possible, effective and seamless cooperation and coordination when and if a crisis situation develops. Communication During Volcanic Emergencies is designed to promote and encourage both of these priorities through providing the first source-book addressing working relationships and inter-linkages between the stakeholder groups, and providing examples of good and bad practice. While targeting the volcanic islands of the eastern Caribbean, the source-book and its content are largely generic, and the advice and guidelines contained therein have equal validity in respect of improving communication before and during crises at any volcano, and have application to the communication issue in respect of a range of other geophysical hazards.

Self-potential anomalies in some Italian volcanic areas

Directory of Open Access Journals (Sweden)

C. Silenziario

1996-06-01

Full Text Available The study of Self-Potential (SP space and time variations in volcanic areas may provide useful information on both the geometrical structure of the volcanic apparatuses and the dynamical behaviour of the feeding and uprising systems. In this paper, the results obtained on the islands of Vulcano (Eolian arc and Ponza (Pontine archipelago and on the Mt. Somma-Vesuvius complex are shown. On the island of Vulcano and on the Mt. Somma-Vesuvius apparatus areal SP surveys were performed with the aim of evidencing anomalies closely associated to the zones of major volcanic activity. On the island of Vulcano a profile across the fumaroles along the crater rim of the Fossa Cone was also carried out in order to have a direct relationship between fumarolic fracture migration and flow rate and SP anomaly space and time variations. The areal survey on the island of Ponza, which is considered an inactive area, is assumed as a reference test with which to compare the amplitude and pattern of the anomalies in the active areas. A tentative interpretation of the SP anomalies in volcanic areas is suggested in terms of electrokinetic phenomena, related to the movement of fluids of both volcanic and non-volcanic origin.

Screening criteria of volcanic hazards aspect in the NPP site evaluation

International Nuclear Information System (INIS)

Nur Siwhan

2013-01-01

Studies have been conducted on the completeness of regulation in Indonesia particularly on volcanic hazards aspects in the evaluation of nuclear power plant site. Volcanic hazard aspect needed to identify potential external hazards that may endanger the safety of the operation of nuclear power plants. There are four stages for evaluating volcanic hazards, which are initial assessment, characterization sources of volcanic activity in the future, screening volcanic hazards and assessment of capable volcanic hazards. This paper discuss the third stage of the general evaluation which is the screening procedure of volcanic hazards. BAPETEN Chairman Regulation No. 2 Year of 2008 has only one screening criteria for missile volcanic phenomena, so it required screening criteria for other hazard phenomena that are pyroclastic flow density; lava flows; avalanche debris materials; lava; opening hole new eruptions, volcano missile; tsunamis; ground deformation; and hydrothermal system and ground water anomaly. (author)

Venus - Volcanic features in Atla Region

Science.gov (United States)

1991-01-01

This Magellan image from the Atla region of Venus shows several types of volcanic features and superimposed surface fractures. The area in the image is approximately 350 kilometers (217 miles) across, centered at 9 degrees south latitude, 199 degrees east longitude. Lava flows emanating from circular pits or linear fissures form flower-shaped patterns in several areas. A collapse depression approximately 20 kilometers by 10 kilometers (12 by 6 miles) near the center of the image is drained by a lava channel approximately 40 kilometers (25 miles) long. Numerous surface fractures and graben (linear valleys) criss-cross the volcanic deposits in north to northeast trends. The fractures are not buried by the lavas, indicating that the tectonic activity post-dates most of the volcanic activity.

Tropical Volcanic Soils From Flores Island, Indonesia

Directory of Open Access Journals (Sweden)

Hikmatullah

2010-01-01

Full Text Available Soils that are developed intropical region with volcanic parent materials have many unique properties, and high potential for agricultural use.The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia,and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed fromandesitic volcanic materials from Flores Island were studied to determine their properties. They were compared intheir physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristicdifferent. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes withdifferent annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed differentproperties compared to the soils derived from volcanic tuff, even though they were developed from the sameintermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences.The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, andvery friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cationexchange capacity (CEC. The soils in western region have higher clay content and showing more developed than ofthe eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order.The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherablemineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soilswere classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands

Variational data assimilation of satellite observations to estimate volcanic ash emissions

NARCIS (Netherlands)

Lu, S.

2017-01-01

Volcanic eruptions release a large amount of volcanic ash, which can pose hazard to human and animal health, land transportation, and aviation safety. Volcanic Ash Transport and Dispersion (VATD) models are critical tools to provide advisory information and timely volcanic ash forecasts. Due to the

Volcanic risk

International Nuclear Information System (INIS)

Rancon, J.P.; Baubron, J.C.

1995-01-01

This project follows the previous multi-disciplinary studies carried out by the French Bureau de Recherches Geologiques et Minieres (BRGM) on the two active volcanoes of the French lesser Antilles: Mt Pelee (Martinique) and Soufriere (Guadeloupe) for which geological maps and volcanic risk studies have been achieved. The research program comprises 5 parts: the study of pyroclastic deposits from recent eruptions of the two volcanoes for a better characterization of their eruptive phenomenology and a better definition of crisis scenarios; the study of deposits and structures of active volcanoes from Central America and the study of eruptive dynamics of andesite volcanoes for a transposition to Antilles' volcanoes; the starting of a methodological multi-disciplinary research (volcanology, geography, sociology...) on the volcanic risk analysis and on the management of a future crisis; and finally, the development of geochemical survey techniques (radon, CO 2 , H 2 O) on active volcanoes of Costa-Rica and Europe (Fournaise, Furnas, Etna) and their application to the Soufriere. (J.S.). 9 refs., 3 figs

Groundwater characteristics and problems in volcanic rock terrains

International Nuclear Information System (INIS)

Custodio, E.

1989-01-01

Volcanic rock formations, each with their own particular hydrogeological characteristics, occur in circumstances that cover a multiplicity of situations. These range from permeable porous rock formations to permeable fissured formations and include all types of intermediate situation between the two. The type of volcanism, distance from the source of emission, age, alteration processes and tectonics are all factors which determine their behaviour. Volcanic formations usually constitute a single aquifer system, even though this may be very heterogeneous and may locally be separated into clearly defined subunits. At times, formations may be hundreds of metres thick and are fairly permeable almost throughout. As a rule, volcanic material does not yield directly soluble salts to the water that flows through it. Mineralization of the water is due to the concentration of rainfall and the hydrolysis of silicates as a result of CO 2 being absorbed from the atmosphere and the ground, or as a result of volcanism itself. Cationic grouping is usually closely correlated to that of the rock formation in which the chemical composition is formed. Most environmental isotope and radioisotope techniques may be used, and at times are of unquestionable value. However, the existence of evaporation in the soil with possible isotopic fractionation, the effects of marked relief, the dilution of dissolved carbon by volcanic carbon and isotopic exchange brought about by volcanic carbon, etc., should be taken into account before valid conclusions are drawn. The paper uses examples taken from existing studies, mainly those being carried out in the Canary Islands (Spain). (author). 98 refs, 18 figs, 4 tabs

Status of volcanism studies for the Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Crowe, B.; Perry, F.; Murrell, M.; Poths, J.; Valentine, G.A. [Los Alamos National Lab., NM (United States); Wells, S. [Univ. of California, Riverside, CA (United States); Bowker, L.; Finnegan, K. [Univ. of Nevada, Las Vegas, NV (United States); Geissman, J.; McFadden, L.

1995-02-01

Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. Geophysical data are described for the YMR and are used as an aid to understand the distribution of basaltic volcanic centers. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the Basin and Range province. The long time of activity and characteristic small volume of the Postcaldera basalt of the YMR result in one of the lowest eruptive rates in a volcanic field in the southwest United States. Chapter 5 summarizes current concepts of the segregation, ascent, and eruption of basalt magma. Chapter 6 summarizes the history of volcanism studies (1979 through early 1994), including work for the Yucca Mountain Site Characterization Project and overview studies by the state of Nevada and the Nuclear Regulatory Commission. Chapter 7 summarizes probabilistic volcanic hazard assessment using a three-part conditional probability model. Chapter 8 describes remaining volcanism work judged to be needed to complete characterization studies for the YMR. Chapter 9 summarizes the conclusions of this volcanism status report.

Status of volcanism studies for the Yucca Mountain Site Characterization Project

International Nuclear Information System (INIS)

Crowe, B.; Perry, F.; Murrell, M.; Poths, J.; Valentine, G.A.; Wells, S.; Bowker, L.; Finnegan, K.; Geissman, J.; McFadden, L.

1995-02-01

Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. Geophysical data are described for the YMR and are used as an aid to understand the distribution of basaltic volcanic centers. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the Basin and Range province. The long time of activity and characteristic small volume of the Postcaldera basalt of the YMR result in one of the lowest eruptive rates in a volcanic field in the southwest United States. Chapter 5 summarizes current concepts of the segregation, ascent, and eruption of basalt magma. Chapter 6 summarizes the history of volcanism studies (1979 through early 1994), including work for the Yucca Mountain Site Characterization Project and overview studies by the state of Nevada and the Nuclear Regulatory Commission. Chapter 7 summarizes probabilistic volcanic hazard assessment using a three-part conditional probability model. Chapter 8 describes remaining volcanism work judged to be needed to complete characterization studies for the YMR. Chapter 9 summarizes the conclusions of this volcanism status report

X-ray microanalysis of volcanic ash

International Nuclear Information System (INIS)

Kearns, S L; Buse, B

2012-01-01

The 2010 eruption of Eyjafjallajökull volcano in Iceland demonstrated the disruptive nature of high-level volcanic ash emissions to the world's air traffic. The chemistry of volcanic material is complex and varied. Different eruptions yield both compositional and morphological variation. Equally a single eruption, such as that in Iceland will evolve over time and may potentially produce a range of volcanic products of varying composition and morphology. This variability offers the petrologist the opportunity to derive a tracer to the origins both spatially and temporally of a single particle by means of electron microbeam analysis. EPMA of volcanic ash is now an established technique for this type of analysis as used in tephrachronology. However, airborne paniculate material may, as in the case of Eyjafjallajökull, result in a particle size that is too small and too dispersed for preparation of standard EPMA mounts. Consequently SEM-EDS techniques are preferred for this type of quantitative analysis . Results of quantitative SEM-EDS analysis yield data with a larger precision error than EPMA yet sufficient to source the original eruption. Uncoated samples analyzed using variable pressure SEM yield slightly poorer results at modest pressures.

Formation and evolution of mesozoic volcanic basins in Gan-Hang tectonic belt

International Nuclear Information System (INIS)

Zhang Xingpu

1999-01-01

The author mainly discusses the principle model for the formation and the evolution of Mesozoic volcanic basins in the Gan-Hang Tectonic Belt, and describes the distinct evolution features between the internal and external sites of volcanic basins, the natural relation between the down-warped, down-faulted, collapse volcanic basins and volcanic domes, the relationship between the formation of inter layered fractured zones of the volcanic cover and the evolution of volcanic basins

Petrogeochemistry of Mesozoic basaltic volcanics in Daqingshan area

International Nuclear Information System (INIS)

Li Xiaoguang; Li Ziying; Wei Sanyuan; Qi Da'neng

2009-01-01

Through the discussion on petrogeochemistry of Later Mesozoic basaltic volcanics in Daqingshan Basin in Manzhouli area, combined with field observation and the predecessors' study, its magma evolution,genesis and diagenetic structural environment are discussed, and some suggestion are provided for the further work. Basaltic magma in this area is believed to be derived from mantle with incompatible elements which were later participated by some crustal materials. It is a partially melting product of mantle by early metasomatized fluid under lithosphere extension. Through petrogeochemical analysis of the volcanics and the contrast to the adjacent uranium-producing volcanics, it is concluded that this region has structural environment to form magma evolution series which are more favorable for volcanic hydrothermal-type uranium and polymetallic mineralization. (authors)

Extravasamento de quimioterápicos: conhecimentos da equipe de enfermagem = Chemotherapeutic’s extravasation: knowledge of the nursing team

Directory of Open Access Journals (Sweden)

Correia, Jefferson Nery

2011-01-01

Full Text Available Objetivo: Analisar o conhecimento da equipe de enfermagem que atua no setor de clínica oncológica de uma instituição hospitalar, quanto à prevenção, identificação e condutas no extravasamento de quimioterápicos intravenosos. Materiais e Métodos: Trata-se de um estudo descritivo exploratório com abordagem qualitativa, realizado por meio de entrevistas gravadas com auxílio de um roteiro semiestruturado, que foram posteriormente transcritas. A análise dos dados foi realizada pela análise de conteúdo e com a literatura pertinente ao assunto. Resultados: Identificaram-se três categorias: o conhecimento sobre quimioterápicos, o extravasamento de quimioterápicos e a necessidade de treinamento sobre quimioterapia. Foi possível observar que o conhecimento de cada indivíduo sobre o assunto é limitado. A equipe percebe a necessidade de educação permanente, pois além de tratar-se de cuidados especializados, há mudanças dos medicamentos antineoplásicos disponíveis. Conclusão: O estudo evidenciou algumas falhas existentes no conhecimento dos profissionais que realizam os cuidados na administração de quimioterápicos em relação à prevenção, identificação e condutas na ocorrência de extravasamento. Infere-se que o treinamento da equipe de enfermagem antes do contato com os pacientes oncológicos e da quimioterapia seja necessário, como também a educação continuada e permanente, garantindo desta maneira maior segurança para os pacientes e atendimento mais humanizado e de qualidade

Fluids in volcanic and geothermal systems

Science.gov (United States)

Sigvaldason, Gudmundur E.

Mineral buffers control the composition of most volatile components of magmas and dissolved species in geothermal fluids. The only element which occurs in significant quantities in volcanic and geothermal fluids and is not controlled by mineral buffers is chlorine. It is argued that in absence of marine influence, geothermal fluids reflect the chlorine content of associated magmatic fluids. The chlorine content of oceanic volcanic rocks has a positive correlation with elements, which are believed to indicate a heterogenous source region. Since the source is generally believed to be the Earth's mantle, the implication is that the mantle is heterogenous with regard to chlorine and other volatiles. Such heterogeneities would have important consequences for genesis and distribution of ore. All major magma types of the oceanic environment occur in Iceland. Their spatial distribution is closely related to a volcanotectonic pattern, suggesting crustal control. A geophysical model of crustal accretion in a rift zone is used in conjunction with classical petrology to predict geochemical processes in a rift zone crust. The model has two kinematic parameters-drift rate and subsidence rate-which combined describe trajectories of mass particles deposited on the surface. When considering in conjunction with thermal gradients of the rift zone a series of metamorphic reactions and chemical fractionation processes are bound to occur, eventually resulting in a layering of the oceanic crust. The physical parameters result in a derived variable, rift zone residence time, which depends on the width of a rift zone. Long residence times in a wide rift zone lead to multistage recycling of material. Other properties of the model, based on geometric arrangement of productive fissure swarms within a rift zone, explain off-rift volcanism as directly related to rift zone processes, either as plate trapped magmatic domains or a transgressive thermal anomaly into an older crust. Off

Embarazo ectópico abdominal en paciente posmenopáusica

OpenAIRE

Jiménez Puñales, Sandi; Fernández Gómez, José; Fleites León, Aracelys; Cruz González, Susel; Sarmiento Benavides, Sulian; Fuentes Hernández, Yander

2015-01-01

La anidación anómala del blastocito se denomina como gestación ectópica. El embarazo ectópico abdominal es una forma rara que se presenta en aproximadamente el 1 % de ellos. Se define como la implantación del producto de la concepción en la cavidad peritoneal, excluyendo las localizaciones tubáricas, ováricas e intraligamentarias. Este es de difícil diagnóstico, pues en muchas ocasiones se realiza de forma tardía. El objetivo del presente trabajo es presentar el caso de una paciente posmenopá...

Drenaje laparoscópico de un seudoquiste pancreático: reporte de caso

Directory of Open Access Journals (Sweden)

B.A. Crisanto-Campos

2012-07-01

Full Text Available Los seudoquistes pancreáticos se definen como colecciones pancreáticas o peripancreáticas homogéneas, no asociadas a tejido necrótico, rodeadas de tejido fibroso o de granulación sin epitelio. El manejo se ha clasificado en quirúrgico (convencional y laparoscópico, y no quirúrgico (endoscópico y radiológico. El objetivo es describir nuestra experiencia inicial en el manejo de un seudoquiste pancreático, con una cistogastroanastomosis posterior laparoscópica, realizada en la Clínica de Páncreas del Hospital General “Dr. Manuel Gea González”, de la Ciudad de México. La cirugía laparoscópica de páncreas es relativamente nueva, las nuevas técnicas e instrumentales han permitido su desarrollo. Nuestra técnica tiene ventajas prácticas confirmadas por otros autores, como una hemostasia sencilla, un ángulo de visión amplio que permite una adecuada necrosectomía, la realización de una anastomosis sin necesidad de engrapadoras, y la posibilidad de resolver otras patologías intraabdominales asociadas, como en este caso.

Lasers in tattoo and pigmentation control: role of the PicoSure® laser system

Directory of Open Access Journals (Sweden)

Torbeck R

2016-05-01

Full Text Available Richard Torbeck,1 Richard Bankowski,2 Sarah Henize,3 Nazanin Saedi,11Department of Dermatology and Cutaneous Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 2Cynosure, Inc, Westford, MA, 3Huron Consulting Group, Chicago, IL, USABackground and objectives: The use of picosecond lasers to remove tattoos has greatly improved due to the long-standing outcomes of nanosecond lasers, both clinically and histologically. The first aesthetic picosecond laser available for this use was the PicoSure® laser system (755/532 nm. Now that a vast amount of research on its use has been conducted, we performed a comprehensive review of the literature to validate the continued application of the PicoSure® laser system for tattoo removal.Study design and methods: A PubMed search was conducted using the term "picosecond" combined with "laser", "dermatology", and "laser tattoo removal".Results: A total of 13 articles were identified, and ten of these met the inclusion criteria for this review. The majority of studies showed that picosecond lasers are an effective and safe treatment mode for the removal of tattoo pigments. Several studies also indicated potential novel applications of picosecond lasers in the removal of various tattoo pigments (eg, black, red, and yellow. Adverse effects were generally mild, such as transient hypopigmentation or blister formation, and were rarely more serious, such as scarring and/or textural change.Conclusion: Advancements in laser technologies and their application in cutaneous medicine have revolutionized the field of laser surgery. Computational modeling provides evidence that the optimal pulse durations for tattoo ink removal are in the picosecond domain. It is recommended that the PicoSure® laser system continue to be used for safe and effective tattoo removal, including for red and yellow pigments.Keywords: tattoo, removal, laser, picosecond 

Farmacovigilancia de fitoterápicos em uma indústria farmacêutica brasileira: mecanismo de aperfeiçoamento dos produtos

Directory of Open Access Journals (Sweden)

Fabiane Sobrinho de ABREU

2014-12-01

Full Text Available A utilização dos fitoterápicos tem como base a tradição popular e é considerada uma opção terapêutica à utilização da medicina convencional. Erroneamente diz-se que o uso desses medicamentos é isento de reações adversas, porém, se não forem utilizados com orientação adequada, podem gerar efeitos nocivos ao organismo. Os medicamentos de forma geral, após serem lançados no mercado, podem provocar reações adversas inesperadas sendo necessário assim, o trabalho da farmacovigilância. Este trabalho teve como objetivo levantar os casos de reações adversas provocadas com a utilização de medicamentos fitoterápicos produzidos por um laboratório nacional sediado no Rio de Janeiro. Um estudo descritivo, retrospectivo, transversal e quantitativo, foi realizado utilizando a base de dados de notificações espontâneas de reações inesperadas da referida indústria, no período de dezoito meses. Durante o período levantado, houve um total de trinta e duas notificações distribuídas entre seis fitoterápicos contendo: Trifolium pratense L, Pinus pinaster Aiton, Hedera helix L., Tribullus terrestris L., Pelargonium sidoides DC., Cimicifuga racemosa (L. Nutt. A reação adversa mais relatada, independente da espécie vegetal utilizada foi alergia. Usuários com idade acima de cinquenta anos predominaram nos relatos, provenientes principalmente da região Sudeste. Conclui-se que a maioria dos medicamentos fitoterápicos produzidos e distribuídos pela indústria é segura e eficaz para o tratamento das patologias a que se destinam. Para que haja um melhor contato entre o notificador e o prescritor, é importante a divulgação da farmacovigilância de fitoterápicos entre os profissionais da Saúde. Dessa forma, é possível conhecer os efeitos nocivos, permitindo ações de aprimoramento do medicamento, e garantindo sua eficácia e segurança.

Estudio de la fauna de aves de la cueva de Pico Ramos (Muskiz, Bizkaia.

Directory of Open Access Journals (Sweden)

P. Castaños

1995-01-01

Full Text Available Se estudian los restos de Aves de la cuenca de Pico Ramos. Destaca entre las especies halladas la presencia de Alca Gigante (Pinguinus impennis a cuya extinción y hallazgos holocenos se dedica especial atención. Se ofrecen datos osteométricos y biogeográficos de las restantes especies.

Volcanic Eruptions and Climate: Outstanding Research Issues

Science.gov (United States)

Robock, Alan

2016-04-01

Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

VOLCANIC TSUNAMI GENERATING SOURCE MECHANISMS IN THE EASTERN CARIBBEAN REGION

Directory of Open Access Journals (Sweden)

George Pararas-Carayannis

2004-01-01

Full Text Available Earthquakes, volcanic eruptions, volcanic island flank failures and underwater slides have generated numerous destructive tsunamis in the Caribbean region. Convergent, compressional and collisional tectonic activity caused primarily from the eastward movement of the Caribbean Plate in relation to the North American, Atlantic and South American Plates, is responsible for zones of subduction in the region, the formation of island arcs and the evolution of particular volcanic centers on the overlying plate. The inter-plate tectonic interaction and deformation along these marginal boundaries result in moderate seismic and volcanic events that can generate tsunamis by a number of different mechanisms. The active geo-dynamic processes have created the Lesser Antilles, an arc of small islands with volcanoes characterized by both effusive and explosive activity. Eruption mechanisms of these Caribbean volcanoes are complex and often anomalous. Collapses of lava domes often precede major eruptions, which may vary in intensity from Strombolian to Plinian. Locally catastrophic, short-period tsunami-like waves can be generated directly by lateral, direct or channelized volcanic blast episodes, or in combination with collateral air pressure perturbations, nuéss ardentes, pyroclastic flows, lahars, or cascading debris avalanches. Submarine volcanic caldera collapses can also generate locally destructive tsunami waves. Volcanoes in the Eastern Caribbean Region have unstable flanks. Destructive local tsunamis may be generated from aerial and submarine volcanic edifice mass edifice flank failures, which may be triggered by volcanic episodes, lava dome collapses, or simply by gravitational instabilities. The present report evaluates volcanic mechanisms, resulting flank failure processes and their potential for tsunami generation. More specifically, the report evaluates recent volcanic eruption mechanisms of the Soufriere Hills volcano on Montserrat, of Mt. Pel

Volcanic systems of Iceland and their magma source

Science.gov (United States)

Sigmarsson, Olgeir

2017-04-01

Several active hot-spot volcanoes produce magma from mantle sources which composition varies on decadal time scale. This is probably best demonstrated by the recent work of Pietruszka and collaborators on Kilauea, Hawaii. In marked contrast, basalt lavas from volcanic system in Iceland located above the presumed centre of the Iceland mantle plume have uniform isotope composition over the last 10 thousand years. Volcanic systems are composed of a central volcano and a fissure swarm, or a combination of both and they represent a fundamental component of the neovolcanic zones in Iceland. Four such systems, those of Askja, Bárðarbunga, Kverkfjöll and Grímsvötn in central Iceland were chosen for investigation. The last three have central volcanoes covered by the Vatnajökull ice-sheet whereas part of their fissure swarms is ice-free. Tephra produced during subglacial eruptions together with lavas from the fissure swarms of Holocene age have been collected and analysed for Sr, Nd and Th isotope ratios. Those volcanic formations that can be univocally correlated to a given volcanic system display uniform isotope ratio but different from one volcanic system to another. An exception to this regularity is that Askja products have isotope ratios indistinguishable from those of Gímsvötn, but since these volcanic systems lies far apart their lava fields do not overlap. A practical aspect of these findings was demonstrated during the rifting event of Bárðarbunga and fissure eruption forming the Holuhraun lava field. Relatively low, O isotope ratios in these basalts and heterogeneous macrocrystal composition have been ascribed to important metabasaltic crustal contamination with or without crystal mush recycling. In that case a surprisingly efficient magma mixing and melt homogenization must have occurred in the past beneath the volcanic systems. One possibility is that during the rapid deglaciation much mantle melting occurred and melts accumulated at the mantle

Explosive Volcanic Activity at Extreme Depths: Evidence from the Charles Darwin Volcanic Field, Cape Verdes

Science.gov (United States)

Kwasnitschka, T.; Devey, C. W.; Hansteen, T. H.; Freundt, A.; Kutterolf, S.

2013-12-01

Volcanic eruptions on the deep sea floor have traditionally been assumed to be non-explosive as the high-pressure environment should greatly inhibit steam-driven explosions. Nevertheless, occasional evidence both from (generally slow-) spreading axes and intraplate seamounts has hinted at explosive activity at large water depths. Here we present evidence from a submarine field of volcanic cones and pit craters called Charles Darwin Volcanic Field located at about 3600 m depth on the lower southwestern slope of the Cape Verdean Island of Santo Antão. We examined two of these submarine volcanic edifices (Tambor and Kolá), each featuring a pit crater of 1 km diameter, using photogrammetric reconstructions derived from ROV-based imaging followed by 3D quantification using a novel remote sensing workflow, aided by sampling. The measured and calculated parameters of physical volcanology derived from the 3D model allow us, for the first time, to make quantitative statements about volcanic processes on the deep seafloor similar to those generated from land-based field observations. Tambor cone, which is 2500 m wide and 250 m high, consists of dense, probably monogenetic medium to coarse-grained volcaniclastic and pyroclastic rocks that are highly fragmented, probably as a result of thermal and viscous granulation upon contact with seawater during several consecutive cycles of activity. Tangential joints in the outcrops indicate subsidence of the crater floor after primary emplacement. Kolá crater, which is 1000 m wide and 160 m deep, appears to have been excavated in the surrounding seafloor and shows stepwise sagging features interpreted as ring fractures on the inner flanks. Lithologically, it is made up of a complicated succession of highly fragmented deposits, including spheroidal juvenile lapilli, likely formed by spray granulation. It resembles a maar-type deposit found on land. The eruption apparently entrained blocks of MORB-type gabbroic country rocks with

Supervolcanoes within an ancient volcanic province in Arabia Terra, Mars.

Science.gov (United States)

Michalski, Joseph R; Bleacher, Jacob E

2013-10-03

Several irregularly shaped craters located within Arabia Terra, Mars, represent a new type of highland volcanic construct and together constitute a previously unrecognized Martian igneous province. Similar to terrestrial supervolcanoes, these low-relief paterae possess a range of geomorphic features related to structural collapse, effusive volcanism and explosive eruptions. Extruded lavas contributed to the formation of enigmatic highland ridged plains in Arabia Terra. Outgassed sulphur and erupted fine-grained pyroclastics from these calderas probably fed the formation of altered, layered sedimentary rocks and fretted terrain found throughout the equatorial region. The discovery of a new type of volcanic construct in the Arabia volcanic province fundamentally changes the picture of ancient volcanism and climate evolution on Mars. Other eroded topographic basins in the ancient Martian highlands that have been dismissed as degraded impact craters should be reconsidered as possible volcanic constructs formed in an early phase of widespread, disseminated magmatism on Mars.

Miocene volcanism in the Oaş-Gutâi Volcanic Zone, Eastern Carpathians, Romania: Relationship to geodynamic processes in the Transcarpathian Basin

Science.gov (United States)

Kovacs, Marinel; Seghedi, Ioan; Yamamoto, Masatsugu; Fülöp, Alexandrina; Pécskay, Zoltán; Jurje, Maria

2017-12-01

We present the first comprehensive study of Miocene volcanic rocks of the Oaş-Gutâi Volcanic Zone (OGVZ), Romania, which are exposed in the eastern Transcarpathian Basin (TB), within the Eastern Alpine-Western Carpathian-Northern Pannonian (ALCAPA) block. Collision between the ALCAPA block and Europe at 18-16 Ma produced the Carpathian fold-and-thrust belt. This was followed by clockwise rotation and an extensional regime forming core complexes of the separated TB fragment. Based on petrographic and geochemical data, including Srsbnd Nd isotopic compositions and Ksbnd Ar ages, we distinguish three types of volcanic activity in the OGVZ: (1) early Miocene felsic volcanism that produced caldera-related ignimbrites in the Gutâi Mountains (15.4-14.8 Ma); (2) widespread middle-late Miocene intermediate/andesitic volcanism (13.4-7.0 Ma); and (3) minor late Miocene andesitic/rhyolitic volcanism comprising the Oraşu Nou rhyolitic volcano and several andesitic-dacitic domes in the Oaş Mountains (11.3-9.5 Ma). We show that magma evolution in the OGVZ was controlled by assimilation-fractional crystallization and magma-mixing processes within an interconnected multi-level crustal magmatic reservoir. The evolution of volcanic activity within the OGVZ was controlled by the geodynamics of the Transcarpathian Basin. The early felsic and late intermediate Miocene magmas were emplaced in a post-collisional setting and were derived from a mantle source region that was modified by subduction components (dominantly sediment melts) and lower crust. The style of volcanism within the eastern TB system exhibits spatial variations, with andesitic composite volcanoes (Gutâi Mountains) observed at the margins, and isolated andesitic-rhyolitic monogenetic volcanoes (Oaş Mountains) in the center of the basin.

Estudio sedimentológico de la cueva sepulcral de Pico Ramos (Muskiz, Biscay.

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P. Areso

1995-01-01

Full Text Available En este trabajo se realiza el estudio de una columna de sedimento del yacimiento de Pico Ramos. No se ven indicadores de frío, ni circuación de agua, aunque la humedad ha sido elevada. Dentro de lo homogeneo de todas las muestras, se ve un ligero empeoramiento que se situaría entre los niveles 3 y 4.

Explosive volcanism, shock metamorphism and the K-T boundary

International Nuclear Information System (INIS)

Desilva, S.L.; Sharpton, V.L.

1988-01-01

The issue of whether shocked quartz can be produced by explosive volcanic events is important in understanding the origin of the K-T boundary constituents. Proponents of a volcanic origin for the shocked quartz at the K-T boundary cite the suggestion of Rice, that peak overpressures of 1000 kbars can be generated during explosive volcanic eruptions, and may have occurred during the May, 1980 eruption of Mt. St. Helens. Attention was previously drawn to the fact that peak overpressures during explosive eruptions are limited by the strength of the rock confining the magma chamber to less than 8 kbars even under ideal conditions. The proposed volcanic mechanisms for generating pressures sufficient to shock quartz are further examined. Theoretical arguments, field evidence and petrographic data are presented showing that explosive volcanic eruptions cannot generate shock metamorphic features of the kind seen in minerals at the K-T boundary

Global time-size distribution of volcanic eruptions on Earth.

Science.gov (United States)

Papale, Paolo

2018-05-01

Volcanic eruptions differ enormously in their size and impacts, ranging from quiet lava flow effusions along the volcano flanks to colossal events with the potential to affect our entire civilization. Knowledge of the time and size distribution of volcanic eruptions is of obvious relevance for understanding the dynamics and behavior of the Earth system, as well as for defining global volcanic risk. From the analysis of recent global databases of volcanic eruptions extending back to more than 2 million years, I show here that the return times of eruptions with similar magnitude follow an exponential distribution. The associated relative frequency of eruptions with different magnitude displays a power law, scale-invariant distribution over at least six orders of magnitude. These results suggest that similar mechanisms subtend to explosive eruptions from small to colossal, raising concerns on the theoretical possibility to predict the magnitude and impact of impending volcanic eruptions.

Un caso de deformación del pico en el tordo cabeza café (Molothrus ater

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Epifanio Blancas-Calva

2013-07-01

Full Text Available Registré la presencia de un individuo macho, probablemente inmaduro, de tordo cabeza café (Molothrus ater con deformación en el pico, en la localidad de Petaquillas, municipio de Chilpancingo, Guerrero. Es necesario realizar estudios para aclarar las causas de la deformación en el pico en esta y otras especies, y si éste es un caso particular o es un fenómeno que afecta a otros individuos u otras especies con distribución en el área. Es importante dilucidar si existe relación entre la patología registrada y la contaminación ambiental en el área por la irrigación de campos de cultivo con aguas residuales de la ciudad de Chilpancingo.

Rejeição de transplantes de córnea: tratamento tópico vs. pulsoterapia - resultados de 10 anos

OpenAIRE

Costa,Dácio Carvalho; Castro,Rosane Silvestre de; Camargo,Mariela Soares Ferraz de; Kara-José,Newton

2008-01-01

OBJETIVOS: Avaliar a eficácia da associação de pulsoterapia com 500 mg de metilprednisolona intravenosa ao acetato de prednisolona 1% tópico no tratamento do primeiro episódio de rejeição endotelial de transplantes de córnea. MÉTODOS: Estudo caso-controle retrospectivo com 81 sujeitos que apresentaram o primeiro episódio de rejeição endotelial e submetidos à terapia nos primeiros quinze dias dos sintomas. RESULTADOS: 67 sujeitos foram tratados com acetato de prednisolona 1% tópico de 1 em 1 h...

SYSTHESIS OF VOLCANISM STUDIES FOR THE YUCCA MOUNTAIN SITE CHARACTERIZATION PROJECT

International Nuclear Information System (INIS)

FV PERRY; GA CROWE; GA VALENTINE; LM BOWKER

1997-01-01

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The hazard of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt ( -7 events per year. Bounding probability estimates are used to assess possible implications of not drilling aeromagnetic anomalies in the Arnargosa Valley and Crater Flat. The results of simulation modeling are used to assess the sensitivity of the disruption probability for the location of northeast boundaries of volcanic zones near the Yucca Mountain site. A new section on modeling of radiological releases associated with surface and subsurface magmatic activity has been added to chapter 6. The modeling results are consistent with past total system performance assessments that show future volcanic and magmatic events are not significant components of repository performance and volcanism is not a priority issue for performance assessment studies

Monitoring and forecasting Etna volcanic plumes

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S. Scollo

2009-09-01

Full Text Available In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV. The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i downloading weather forecast data from meteorological mesoscale models; ii running models of tephra dispersal, iii plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed.

Susceptibility mapping in the Río El Estado watershed, Pico de Orizaba volcano, Mexico

Science.gov (United States)

Legorreta Paulin, G.; Bursik, M. I.; Lugo Hubp, J.; Paredes Mejía, L.; Aceves Quesada, F.

2013-12-01

In volcanic terrains, dormant stratovolcanoes are very common and can trigger landslides and debris flows continually along stream systems, thereby affecting human settlements and economic activities. It is important to assess their potential impact and damage through the use of landslide inventory maps and landslide models. This poster provides an overview of the on-going research project (Grant SEP-CONACYT no 167495) from the Institute of Geography at the National Autonomous University of Mexico (UNAM) that seeks to conduct a multi-temporal landslide inventory and produce a landslide susceptibility map by using Geographic Information Systems (GIS). The Río El Estado watershed on the southwestern flank of Pico de Orizaba volcano, the highest mountain in Mexico, is selected as a study area. The catchment covers 5.2 km2 with elevations ranging from 2676.79 to 4248.2 m a.s.l. and hillslopes between 5° and 56°. The stream system of Río El Estado catchment erodes Tertiary and Quaternary lavas, pyroclastic flows, and fall deposits. The geologic and geomorphologic factors in combination with high seasonal precipitation, high degree of weathering, and steep slopes predispose the study area to landslides. The method encompasses two main levels of analysis to assess landslide susceptibility. The first level builds a historic landslide inventory. In the study area, an inventory of more than 100 landslides was mapped from interpretation of multi-temporal aerial orthophotographs and local field surveys to assess and describe landslide distribution. All landslides were digitized into a GIS, and the spatial geo-database of landslides was constructed from standardized GIS datasets. The second level calculates the susceptibility for the watershed. Multiple Logistic Regression (MLR) was used to examine the relationship between landsliding and several independent variables (elevation, slope, terrain curvature, flow direction, saturation, contributing area, land use, and geology

Global volcanic earthquake swarm database and preliminary analysis of volcanic earthquake swarm duration

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S. R. McNutt

1996-06-01

Full Text Available Global data from 1979 to 1989 pertaining to volcanic earthquake swarms have been compiled into a custom-designed relational database. The database is composed of three sections: 1 a section containing general information on volcanoes, 2 a section containing earthquake swarm data (such as dates of swarm occurrence and durations, and 3 a section containing eruption information. The most abundant and reliable parameter, duration of volcanic earthquake swarms, was chosen for preliminary analysis. The distribution of all swarm durations was found to have a geometric mean of 5.5 days. Precursory swarms were then separated from those not associated with eruptions. The geometric mean precursory swarm duration was 8 days whereas the geometric mean duration of swarms not associated with eruptive activity was 3.5 days. Two groups of precursory swarms are apparent when duration is compared with the eruption repose time. Swarms with durations shorter than 4 months showed no clear relationship with the eruption repose time. However, the second group, lasting longer than 4 months, showed a significant positive correlation with the log10 of the eruption repose period. The two groups suggest that different suites of physical processes are involved in the generation of volcanic earthquake swarms.

Volcanic deformation in the Andes

Science.gov (United States)

Riddick, S.; Fournier, T.; Pritchard, M.

2009-05-01

We present the results from an InSAR survey of volcanic activity in South America. We use data from the Japanese Space Agency's ALOS L-band radar satellite from 2006-2009. The L-band instrument provides better coherence in densely vegetated regions, compared to the shorter wave length C-band data. The survey reveals volcano related deformation in regions, north, central and southern, of the Andes volcanic arc. Since observations are limited to the austral summer, comprehensive coverage of all volcanoes is not possible. Yet, our combined observations reveal volcanic/hydrothermal deformation at Lonquimay, Llaima, Laguna del Maule, and Chaitén volcanoes, extend deformation measurements at Copahue, and illustrate temporal complexity to the previously described deformation at Cerro Hudson and Cordón Caulle. No precursory deformation is apparent before the large Chaitén eruption (VEI_5) of 2 May 2008, (at least before 16 April) suggesting rapid magma movement from depth at this long dormant volcano. Subsidence at Ticsani Volcano occurred coincident with an earthquake swarm in the same region.

Desenvolvimento de equações para estimativa do VO2PICO pelo teste de 9 minutos

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Ana Carolina Paludo

2014-06-01

Full Text Available OBJETIVO: Desenvolver e validar modelos matemáticos para predição do VO2pico em crianças e adolescentes, por meio da utilização do teste de campo de corrida/caminhada de 9 minutos. MÉTODOS: Foram avaliados 211 escolares, de sete a 12 anos de idade, de ambos os sexos, regularmente matriculados em duas escolas do Município de Londrina - PR, sendo 141 escolares separados para amostra de desenvolvimento e 70 para validação das equações desenvolvidas. As medidas avaliadas foram: massa corporal, estatura, espessuras de dobras cutâneas (tricipital e subescapular, além da maturação biológica. Os testes de corrida/caminha de 9 minutos foram realizados em pista de atletismo e a análise direta do VO2pico (mL/kg/min realizada em laboratório, com analisador de gás portátil, através um teste incremental em esteira rolante. O desenvolvimento das equações foi realizado através da análise de regressão linear pelo método stepwise e a validação foi realizada pelos testes matemáticos específicos levando em consideração uma significância de 5% para todas as análises. RESULTADOS: A equação geral para a amostra total foi VO2pico= 24,506+16,672 (maturação, 0=pré e 1=púbere e pós - 0,346 (Σ DC + 5,187 (sexo, 0=F e 1=M + 0,009 (distância com um r=0,742 e EPE=9,149 mL/kg/min e sua validação apresentou r=0,570, CCI= 0,68, limites de concordância de -1,4 mL/kg/min, EPE=8,39 mL/kg/min e CV= 21,94%. CONCLUSÃO: Conclui-se que a equação generalizada desenvolvida fornece uma estimativa válida do VO2pico em crianças e adolescentes de sete a 12 anos de idade.

Combined use of FRN and CSSI techniques: SWMCN Laboratory PICO experience during the European Geosciences Union (EGU) General Assembly 2015, Vienna, Austria

International Nuclear Information System (INIS)

Mabit, L.; Toloza, A.; Resch, C.

2016-01-01

The European Geosciences Union (EGU) General Assembly 2015 that took place at the Austria Center of Vienna, from 12-17 April 2015, was a big success with 4870 oral, 8489 poster, and 705 PICO (Presenting Interactive COntent™) presentations as well as 11837 scientists attending from 108 different countries. This year again, the activities of the SWMCN Laboratory were well represented with 3 PICO presentations during the SSS12.10 session (i.e. Soil and sediment tracing techniques for understanding environmental processes)

Monitoring the Sumatra volcanic arc with InSAR

Science.gov (United States)

Chaussard, E.; Hong, S.; Amelung, F.

2009-12-01

The Sumatra volcanic arc is the result of the subduction of the Indo-Australian plate under the Sunda plate. The arc consists of 35 known volcanic centers, subaerials on the west coast of the Sumatra and Andaman Islands and submarines between these islands. Six active centers are known in the Sumatra volcanic arc. Surface deformation in volcanic areas usually indicates movement of magma or hydrothermal fluids at depth. Here we present a satellite-based Interferometric synthetic aperture radar (InSAR) survey of the Sumatra volcanic arc using ALOS data. Spanning the years 2007 to beginning of 2009, our survey reveals the background level of activity of the 35 volcanoes. We processed data from 40 tracks (24 in descending orbit and 16 in ascending orbit) to cover the whole Sumatra arc. In the first results five of these six known active centers show no sign of activity: Dempo, Kaba, Marapi, Talang and Peuet. The remaining active volcano, Mount Kerinci, has an ambiguous signal. We used pair-wise logic and InSAR time series of the available ALOS data to determine if the observed InSAR signal is caused by ground deformation or by atmospheric delays.

Global monsoon precipitation responses to large volcanic eruptions.

Science.gov (United States)

Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

2016-04-11

Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do.

Embarazo ectópico en cicatriz de cesárea. Presentación de un caso

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Martha Lucía Marrugo-Flórez

2013-01-01

Full Text Available El embarazo ectópico en cicatriz de cesárea anterior corresponde aproximadamente al 6,1 % de todos los embarazos ectópicos y tiene una incidencia mayor que el embarazo cervical dentro del grupo mencionado. Consiste en la implantación del blastocito en la cicatriz uterina, rodeado de miometrio y tejido conectivo. El manejo de esta patología ha sido controversial a lo largo de los años, debido a que ocurre en muchas mujeres que desean conservar su paridad. Presentamos un caso atendido en marzo en nuestra institución, en el que se realizó manejo médico con metrotexate sistémico e intraamniótico y presentó una evolución satisfactoria. Se realiza una revisión del tema y se explican los diferentes manejos propuestos para esta patología.

Reservoir Space Evolution of Volcanic Rocks in Deep Songliao Basin, China

Science.gov (United States)

Zheng, M.; Wu, X.; Zheng, M.; HU, J.; Wang, S.

2015-12-01

Recent years, large amount of natural gas has been discovered in volcanic rock of Lower Crataceous of Songliao basin. Volcanic reservoirs have become one of the important target reservoir types of eastern basin of China. In order to study the volcanic reservoirs, we need to know the main factors controlling the reservoir space. By careful obsercation on volcanic drilling core, casting thin sections and statistical analysis of petrophysical properties of volcanic reservoir in Songliao basin, it can be suggested that the igneous rock reservoir in Yingcheng formation of Lower Crataceous is composed of different rock types, such ad rohylite, rohylitic crystal tuff, autoclastic brecciation lava and so on. There are different reservoirs storage space in in various lithological igneous rocks, but they are mainly composed of primary stoma, secondary solution pores and fractures.The evolution of storage space can be divided into 3 stage: the pramary reservoir space,exogenic leaching process and burial diagenesis.During the evolution process, the reservoir space is effected by secondary minerals, tectonic movement and volcanic hydrothermal solution. The pore of volcanic reservoirs can be partially filled by secondary minerals, but also may be dissoluted by other chemical volcanic hydrothermal solution. Therefore, the favorable places for better-quality volcanic reservoirs are the near-crater facies of vocanic apparatus and dissolution zones on the high position of paleo-structures.

Eruptive and environmental processes recorded by diatoms in volcanically-dispersed lake sediments from the Taupo Volcanic Zone, New Zealand

Science.gov (United States)

Harper, Margaret A.; Pledger, Shirley A.; Smith, Euan G. C.; Van Eaton, Alexa; Wilson, Colin J. N.

2015-01-01

Late Pleistocene diatomaceous sediment was widely dispersed along with volcanic ash (tephra) across and beyond New Zealand by the 25.4 ka Oruanui supereruption from Taupo volcano. We present a detailed analysis of the diatom populations in the Oruanui tephra and the newly discovered floras in two other eruptions from the same volcano: the 28.6 ka Okaia and 1.8 ka Taupo eruptions. For comparison, the diatoms were also examined in Late Pleistocene and Holocene lake sediments from the Taupo Volcanic Zone (TVZ). Our study demonstrates how these microfossils provide insights into the lake history of the TVZ since the Last Glacial Maximum. Morphometric analysis of Aulacoseira valve dimensions provides a useful quantitative tool to distinguish environmental and eruptive processes within and between individual tephras. The Oruanui and Okaia diatom species and valve dimensions are highly consistent with a shared volcanic source, paleolake and eruption style (involving large-scale magma-water interaction). They are distinct from lacustrine sediments sourced elsewhere in the TVZ. Correspondence analysis shows that small, intact samples of erupted lake sediment (i.e., lithic clasts in ignimbrite) contain heterogeneous diatom populations, reflecting local variability in species composition of the paleolake and its shallowly-buried sediments. Our analysis also shows a dramatic post-Oruanui supereruption decline in Cyclostephanos novaezelandiae, which likely reflects a combination of (1) reorganisation of the watershed in the aftermath of the eruption, and (2) overall climate warming following the Last Glacial Maximum. This decline is reflected in substantially lower proportions of C. novaezelandiae in the 1.8 ka Taupo eruption deposits, and even fewer in post-1.8 ka sediments from modern (Holocene) Lake Taupo. Our analysis highlights how the excellent preservation of siliceous microfossils in volcanic tephra may fingerprint the volcanic source region and retain a valuable record

Régimen jurídico aplicable a los contratos atípicos en la jurisprudencia colombiana

OpenAIRE

Maria Elisa Camacho López

2005-01-01

El presente artículo tiene por objeto, explicar el desarrollo que ha tenido el tema de los contratos atípicos en la jurisprudencia colombiana, haciendo especial énfasis en los mecanismos sugeridos para determinar su régimen jurídico aplicable.

Volcanic passive margins: another way to break up continents.

Science.gov (United States)

Geoffroy, L; Burov, E B; Werner, P

2015-10-07

Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.

Microbiological, chemical, and sensory changes in irradiated pico de gallo

International Nuclear Information System (INIS)

Howard, L.R.; Miller, G.H. Jr.; Wagner, A.B.

1995-01-01

The effects of gamma processing (1 kGy) and refrigerated storage (2 degrees C) on microbiological, sensory, and chemical quality of pico de gallo was studied. Color, flavor, texture, odor, and heat sensory attributes were not affected by radiation treatment. The treatment decreased populations of aerobic mesophilic, heterofermentative, and total lactic microflora during storage. L-ascorbic acid content declined 50% in response to gamma processing, but levels were similar in irradiated and non-irradiated samples after 6 wk. Pectin solubility was affected by radiation treatment. Gamma processing caused a reduction in pectin degree of estenfication, and conversion of chelator soluble to dilute alkali soluble and nonextractable pectins

Ozone depletion following future volcanic eruptions

Science.gov (United States)

Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

2017-07-01

While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

Deriving spatial patterns from a novel database of volcanic rock geochemistry in the Virunga Volcanic Province, East African Rift

Science.gov (United States)

Poppe, Sam; Barette, Florian; Smets, Benoît; Benbakkar, Mhammed; Kervyn, Matthieu

2016-04-01

The Virunga Volcanic Province (VVP) is situated within the western branch of the East-African Rift. The geochemistry and petrology of its' volcanic products has been studied extensively in a fragmented manner. They represent a unique collection of silica-undersaturated, ultra-alkaline and ultra-potassic compositions, displaying marked geochemical variations over the area occupied by the VVP. We present a novel spatially-explicit database of existing whole-rock geochemical analyses of the VVP volcanics, compiled from international publications, (post-)colonial scientific reports and PhD theses. In the database, a total of 703 geochemical analyses of whole-rock samples collected from the 1950s until recently have been characterised with a geographical location, eruption source location, analytical results and uncertainty estimates for each of these categories. Comparative box plots and Kruskal-Wallis H tests on subsets of analyses with contrasting ages or analytical methods suggest that the overall database accuracy is consistent. We demonstrate how statistical techniques such as Principal Component Analysis (PCA) and subsequent cluster analysis allow the identification of clusters of samples with similar major-element compositions. The spatial patterns represented by the contrasting clusters show that both the historically active volcanoes represent compositional clusters which can be identified based on their contrasted silica and alkali contents. Furthermore, two sample clusters are interpreted to represent the most primitive, deep magma source within the VVP, different from the shallow magma reservoirs that feed the eight dominant large volcanoes. The samples from these two clusters systematically originate from locations which 1. are distal compared to the eight large volcanoes and 2. mostly coincide with the surface expressions of rift faults or NE-SW-oriented inherited Precambrian structures which were reactivated during rifting. The lava from the Mugogo

First volcanic CO2 budget estimate for three actively degassing volcanoes in the Central American Volcanic Arc

Science.gov (United States)

Robidoux, Philippe; Aiuppa, Alessandro; Conde, Vladimir; Galle, Bo; Giudice, Gaetano; Avard, Geoffroy; Muñoz, Angélica

2014-05-01

CO2 is a key chemical tracer for exploring volcanic degassing mechanisms of basaltic magmatic systems (1). The rate of CO2 release from sub-aerial volcanism is monitored via studies on volcanic plumes and fumaroles, but information is still sparse and incomplete for many regions of the globe, including the majority of the volcanoes in the Central American Volcanic Arc (2). Here, we use a combination of remote sensing techniques and in-situ measurements of volcanic gas plumes to provide a first estimate of the CO2 output from three degassing volcanoes in Central America: Turrialba, in Costa Rica, and Telica and San Cristobal, in Nicaragua. During a field campaign in March-April 2013, we obtained (for the three volcanoes) a simultaneous record of SO2 fluxes (from the NOVAC network (3)) and CO2 vs. SO2 concentrations in the near-vent plumes (obtained via a temporary installed fully-automated Multi-GAS instrument (4)). The Multi-GAS time-series allowed to calculate the plume CO2/SO2 ratios for different intervals of time, showing relatively stable gas compositions. Distinct CO2 - SO2 - H2O proportions were observed at the three volcanoes, but still within the range of volcanic arc gas (5). The CO2/SO2 ratios were then multiplied by the SO2 flux in order to derive the CO2 output. At Turrialba, CO2/SO2 ratios fluctuated, between March 12 and 19, between 1.1 and 5.7, and the CO2flux was evaluated at ~1000-1350 t/d (6). At Telica, between March 23 and April 8, a somewhat higher CO2/SO2 ratio was observed (3.3 ± 1.0), although the CO2 flux was evaluated at only ~100-500 t/d (6). At San Cristobal, where observations were taken between April 11 and 15, the CO2/SO2 ratio ranged between 1.8 and 7.4, with a mean CO2 flux of 753 t/d. These measurements contribute refining the current estimates of the total CO2 output from the Central American Volcanic Arc (7). Symonds, R.B. et al., (2001). J. Volcanol. Geotherm. Res., 108, 303-341 Burton, M. R. et al. (2013). Reviews in

The volcanism of the western part of the Los Frailes Meseta (Bolivia): a representative example of the Andean volcanism since the Upper Oligocene

International Nuclear Information System (INIS)

Leroy, L.; Jimenez, N.

1996-01-01

The Los Frailes Meseta (Bolivia) is one of the large tertiary ignimbritic fields of the inner volcanic arc from Central Andes (Central Volcanic Zone. CVZ), in contact zone between the Altiplano to the west and the Eastern Cordillera to the east. Field observations and mineralogical and geochemical studies (major and trace elements) lead to distinguish two types of volcanism in the western border to the Meseta. During the Middle Miocene and Pliocene, the volcanic activity can be subdivided into three pyroclastic emission cycles, the Larco, Coroma and Pliocene ignimbrites, the first two being separated by the Quechua 2 orogeny. All these ignimbrites are very similar and correspond to peraluminous rhyolites to rhyodacites. In the studies area, the Coroma cycle is the only one where an ignimbrite-less evolved resurgent dome association can be observed. Beside these ignimbrites, isolated small lava flows and domes overlay and/or intrude all the other formations. They are meta-aluminous lavas with a shoshonitic affinity. A quaternary age can be attributed to his second volcanism. These two volcanic types are well-known in the CVZ and are related to the different deformation stages, either compressional or extensional, which occur alternately in the Cordillera since 26 Ma. (authors). 61 refs., 12 figs., 3 tabs

Evidence for volcanism in NW Ishtar Terra, Venus

International Nuclear Information System (INIS)

Gaddis, L.; Greeley, R.

1989-01-01

Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas

Geochemistry of volcanic series of Aragats province

International Nuclear Information System (INIS)

Meliksetyan, Kh.B.

2012-01-01

In this contribution we discuss geochemical and isotope characteristics of volcanism of the Aragats volcanic province and possible petrogenetical models of magma generation in collision zone of Armenian highland. We talk about combination of some specific features of collision related volcanism such as dry and high temperature conditions of magma generation, that demonstrate some similarities to intraplate-like petrogenesis and presence of mantle source enriched by earlier subductions, indicative to island-arc type magma generation models. Based on comprehensive analysis of isotope and geochemical data and some published models of magma generation beneath Aragats we lead to a petrogenetic model of origin of Aragats system to be a result of magma mixture between mantle originated mafic magma with felsic, adakite-type magmas

Relação entre a variabilidade da frequência cardíaca e VO 2pico em mulheres ativas

OpenAIRE

Tamburús, Nayara Yamada; Rebelo, Ana Cristina Silva; César, Marcelo de Castro; Catai, Aparecida Maria; Takahashi, Anielle Cristhine de Medeiros; Andrade, Carolina Pieroni; Porta, Alberto; Silva, Ester da

2014-01-01

OBJETIVO: Ava+liar a associação entre os índices da variabilidade da frequência cardíaca (VFC) e a aptidão cardiorrespiratória.MÉTODOS: Sessenta e duas mulheres (idade 22,1 ± 3,3 anos) foram divididas em quatro grupos: treinamento aeróbio (AER, n = 15), treinamento de força (FOR, n = 13), treinamento combinado (aeróbio e força) (AER+FOR, n = 15) e controle (C, n = 19). O teste cardiopulmonar foi realizado para avaliar a aptidão cardiorrespiratória a partir do consumo de oxigênio pico (VO2pico...

Global monsoon precipitation responses to large volcanic eruptions

Science.gov (United States)

Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

2016-01-01

Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do. PMID:27063141

Radon gas as a tracer for volcanic processes

International Nuclear Information System (INIS)

Thomas, D.M.

1990-01-01

Radon emissions from volcanic systems have been under investigation for several decades. Soil gas and groundwater radon activities have been used to map faults and to characterize geothermal systems, and measurements of atmospheric radon and radon daughter concentrations have been used to estimate the volume of magma chambers feeding active eruptions. Several studies have also shown that temporal variations in radon concentration have been associated with the onset of volcanic eruptions or changes in the rates or character of an eruption. Some of these studies have been able to clearly define the cause of the radon anomalies but others have proposed models of radon emission and transport that are not well supported by the known physical and chemical processes that occur in a volcanic system. In order to better characterize the processes that control radon activities in volcanic systems, it is recommended that future radon monitoring programs attempt to maintain continuous recording of radon activities; individual radon measurements should be made over the shortest time intervals possible that are consistent with acceptable counting statistics and geophysical, meteorological, and hydrological parameters should be measured in order to better define the physical processes that affect radon activities in volcanic systems. (author). 63 refs

Production of low molecular weight hydrocarbons by volcanic eruptions on early Mars.

Science.gov (United States)

Segura, Antígona; Navarro-González, Rafael

2005-10-01

Methane and other larger hydrocarbons have been proposed as possible greenhouse gases on early Mars. In this work we explore if volcanic processes may have been a source for such molecules based on theoretical and experimental considerations. Geologic evidence and numerical simulations indicate that explosive volcanism was widely distributed throughout Mars. Volcanic lightning is typically produced in such explosive volcanism. Therefore this geologic setting was studied to determine if lightning could be a source for hydrocarbons in volcanic plumes. Volcanic lightning was simulated by focusing a high-energy infrared laser beam inside of a Pyrex reactor that contained the proposed volcanic gas mixture composed of 64% CH(4), 24% H(2), 10% H(2)O and 2% N(2), according to an accretion model and the nitrogen content measured in Martian meteorites. The analysis of products was performed by gas chromatography coupled to infrared and mass spectroscopy. Eleven hydrocarbons were identified among the products, of which acetylene (C(2)H(2)) was the most abundant. A thermochemical model was used to determine which hydrocarbons could arise only from volcanic heat. In this case, acetylene and ethylene are formed at magmatic temperatures. Our results indicate that explosive volcanism may have injected into the atmosphere of early Mars approximately 6 x 10(12) g yr(-1) of acetylene, and approximately 2 x 10(12) g yr(-1) of 1,3-butadiyne, both produced by volcanic lightning, approximately 5 x 10(11) g yr(-1) of ethylene produced by volcanic heat, and 10(13) g yr(-1) of methane.

Efficiency Enhancement of Pico-cell Base Station Power Amplifier MMIC in Gallium Nitride HFET Technology Using the Doherty technique

Science.gov (United States)

Seneviratne, Sashieka

With the growth of smart phones, the demand for more broadband, data centric technologies are being driven higher. As mobile operators worldwide plan and deploy 4th generation (4G) networks such as LTE to support the relentless growth in mobile data demand, the need for strategically positioned pico-sized cellular base stations known as 'pico-cells' are gaining traction. In addition to having to design a transceiver in a much compact footprint, pico-cells must still face the technical challenges presented by the new 4G systems, such as reduced power consumptions and linear amplification of the signals. The RF power amplifier (PA) that amplifies the output signals of 4G pico-cell systems face challenges to minimize size, achieve high average efficiencies and broader bandwidths while maintaining linearity and operating at higher frequencies. 4G standards as LTE use non-constant envelope modulation techniques with high peak to average ratios. Power amplifiers implemented in such applications are forced to operate at a backed off region from saturation. Therefore, in order to reduce power consumption, a design of a high efficiency PA that can maintain the efficiency for a wider range of radio frequency signals is required. The primary focus of this thesis is to enhance the efficiency of a compact RF amplifier suitable for a 4G pico-cell base station. For this aim, an integrated two way Doherty amplifier design in a compact 10mm x 11.5mm2 monolithic microwave integrated circuit using GaN device technology is presented. Using non-linear GaN HFETs models, the design achieves high effi-ciencies of over 50% at both back-off and peak power regions without compromising on the stringent linearity requirements of 4G LTE standards. This demonstrates a 17% increase in power added efficiency at 6 dB back off from peak power compared to conventional Class AB amplifier performance. Performance optimization techniques to select between high efficiency and high linearity operation are

TRANSFORMACIONES ALREDEDOR DEL DISCURSO, PRÁCTICAS EDUCATIVAS, ACTITUDES Y RELACIONES SOCIALES DE LAS MADRES COMUNITARIAS DEL ICBF. "Pueblo Viejo" (Magdalena y el programa "Nichos Pedagógicos"

Directory of Open Access Journals (Sweden)

Mónica Borjas

2009-01-01

Full Text Available Este artículo presenta los resultados de un proceso de investigación que da cuenta de las transformaciones que las madres comunitarias tuvieron en torno a su discurso, práctica educativa y relaciones sociales, en el seno del programa de capacitación "Nichos Pedagógicos", orientado por el Instituto de Estudios en Educación iese, de la Universidad del Norte, bajo el patrocinio de la fundación promigas. Inicialmente, se exponen los referentes contextuales relacionados con los aspectos misionales del Instituto Colombiano de Bienestar Familiar -icbf-y con el municipio de Pueblo Viejo, Magdalena (Colombia, lugar de origen de las madres comunitarias participantes. En segunda instancia, se presentan los referentes de teóricos de las categorías de análisis: Discurso, prácticas e interacciones y, finalmente, se expone una conceptualización de "Nicho Pedagógico", denominación del Programa de Capacitación ofrecido a las madres comunitarias.

Strike-slip pull-apart process and emplacement of Xiangshan uranium-producing volcanic basin

International Nuclear Information System (INIS)

Qiu Aijin; Guo Lingzhi; Shu Liangshu

2001-01-01

Xiangshan volcanic basin is one of the famous uranium-producing volcanic basins in China. Emplacement mechanism of Xiangshan uranium-producing volcanic basin is discussed on the basis of the latest research achievements of deep geology in Xiangshan area and the theory of continental dynamics. The study shows that volcanic activity in Xiangshan volcanic basin may be divided into two cycles, and its emplacement is controlled by strike-ship pull-apart process originated from the deep regional faults. Volcanic apparatus in the first cycle was emplaced in EW-trending structure activated by clockwise strike-slipping of NE-trending deep fault, forming the EW-trending fissure-type volcanic effusion belt. Volcanic apparatus in the second cycle was emplaced at junction points of SN-trending pull-apart structure activated by sinistral strike-slipping of NE-trending deep faults and EW-trending basement faults causing the center-type volcanic magma effusion and extrusion. Moreover, the formation mechanism of large-rich uranium deposits is discussed as well

Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone

Science.gov (United States)

Moussallam, Yves; Tamburello, Giancarlo; Peters, Nial; Apaza, Fredy; Schipper, C. Ian; Curtis, Aaron; Aiuppa, Alessandro; Masias, Pablo; Boichu, Marie; Bauduin, Sophie; Barnie, Talfan; Bani, Philipson; Giudice, Gaetano; Moussallam, Manuel

2017-09-01

Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO2 flux of 15.3 ± 2.3 kg s- 1 (1325-ton day- 1) at Sabancaya and of 11.4 ± 3.9 kg s- 1 (988-ton day- 1) at Ubinas using scanning ultraviolet spectroscopy and dual UV camera systems. In-situ Multi-GAS analyses yield molar proportions of H2O, CO2, SO2, H2S and H2 gases of 73, 15, 10 1.15 and 0.15 mol% at Sabancaya and of 96, 2.2, 1.2 and 0.05 mol% for H2O, CO2, SO2 and H2S at Ubinas. Together, these data imply cumulative fluxes for both volcanoes of 282, 30, 27, 1.2 and 0.01 kg s- 1 of H2O, CO2, SO2, H2S and H2 respectively. Sabancaya and Ubinas volcanoes together contribute about 60% of the total CO2 emissions from the Central Volcanic zone, and dominate by far the total revised volatile budget of the entire Central Volcanic Zone of the Andes.

Texturas de los minerales del grupo de la sílice de la manifestación epitermal El Rifle-Hato Viejo, región de Moa: clasificación, descripción e implicaciones genéticas

Directory of Open Access Journals (Sweden)

Leduar Ramayo-Cortés

2001-03-01

Full Text Available En el marco de la región de Moa, Cuba oriental, se localizan varias manifestaciones hidrotermales. Se trata de sistemas vetiformes y brechas hidrotermales con contenidos significativos de metales nobles. La manifestación hidrotermal El Rifle-Hato Viejo se destaca por su extensión, y está formada por brechas y vetas de cuarzo mineralizadas, vinculadas preferentemente a fracturas correspondientes al sistema de fallas NW-SE y se hospeda en rocas sedimentarias del Campaniense Tardío-Daniense. El estudio textural de los minerales del grupo de la sílice permitió el reconocimiento de varias texturas, las cuales fueron clasificadas en tres grupos: 1 texturas de crecimiento primario (calcedonia maciza, costriforme, en peine, cristales zonados, y maciza, 2 texturas de recristalización (mosaico, plumosa y llameante, y 3 texturas de reemplazo (en enrejado, paralelo y radiado. Sobre la base de este análisis se estableció la secuencia deposicional de los diferentes minerales del grupo de la sílice y se reveló la presencia de la paragénesis de alteración adularia-sericita, lo cual indicaría el desarrollo de un sistema epitermal de baja sulfuración. Estas texturas también se usaron para indicar el nivel de emplazamiento dentro del sistema epitermal; en este caso, el emplazamiento de la manifestación El Rifle-Hato Viejo se corresponde con el nivel intermedio o coloiforme-costriforme, el cual se encuentra por encima de la zona propicia para la deposición del oro, por lo que podría esperarse la presencia de contenidos más elevados en profundidad.

Nature and origin of secondary mineral coatings on volcanic rocks of the Black Mountain, Stonewall Mountain, and Kane Springs Wash volcanic centers, southern, Nevada

Science.gov (United States)

Taranik, James V.; Hsu, Liang C.; Spatz, David M.; Chenevey, Michael J.

1989-01-01

The following subject areas are covered: (1) genetic, spectral, and LANDSAT Thematic Mapper imagery relationship between desert varnish and tertiary volcanic host rocks, southern Nevada; (2) reconnaissance geologic mapping of the Kane Springs Wash Volcanic Center, Lincoln County, Nevada, using multispectral thermal infrared imagery; (3) interregional comparisons of desert varnish; and (4) airborne scanner (GERIS) imagery of the Kane Springs Wash Volcanic Center, Lincoln County, Nevada.

Steam sterilization of previously-assembled laparoscopic instruments Esterilización por vapor de los instrumentos laparoscópicos previamente armados Esterilização pelo vapor dos instrumentos laparoscópicos previamente montados

Directory of Open Access Journals (Sweden)

Tamara Carolina de Camargo

2008-01-01

Full Text Available Video-laparoscopy represents one of the greatest surgical advances in the recent past. Reprocessable laparoscopic instruments are complex devices that, if completely disassembled for sterilization, would cause problems for the surgical teams at the moment of their use in the surgery. The method of choice for the sterilization of this equipment is saturated steam under pressure. The goal of this review was to describe the state-of-the-art in the search for safe results in autoclaving the previously-assembled reprocessable laparoscopic instruments, since they are difficult to assemble at the moment of surgery. The PUBMED database was consulted, using controlled and free keywords, as well as their combinations, without time or language restrictions. The study investigating the exact issue of this research found contamination in both assembled (1/24 and disassembled (1/30 instruments, demonstrating equivalent risks. In view of the results and considering the lack of studies, a new experimental laboratory study is recommended, using a contamination challenge.El video-laparoscopía representa uno de los mayores avances en el área de la cirugía en los últimos tiempos. Los instrumentos laparoscópicos reprocesables son artículos complejos, que si son esterilizados totalmente desarmados ocasionan trastornos a los equipos quirúrgicos en el momento de su utilización en el campo operatorio. El método de elección para la esterilización de esos instrumentos es el vapor saturado bajo presión. El objetivo de esta revisión fue describir el estado del arte en búsqueda de los resultados de la seguridad en el autoclavado del instrumental laparoscópico reprocesable, previamente armado, teniendo presente las dificultades de su montaje en el momento de la cirugía. Se consultó la base de datos PUBMED, usando vocablos controlados, libres y la combinación de ambos, sin restricción de tiempo e idioma. Fueron localizados apenas dos artículos que

Compositional Differences between Felsic Volcanic rocks from the ...

African Journals Online (AJOL)

The elemental and Sr-Nd isotopic compositions of the volcanic rocks suggest that fractional crystallization from differing basic parents accompanied by a limited assimilation (AFC) was the dominant process controlling the genesis of the MER felsic volcanic rocks. Keywords: Ethiopia; Northern Main Ethiopian Rift; Bimodal ...

Eruptive history of the Elysium volcanic province of Mars

International Nuclear Information System (INIS)

Tanaka, K.L.; Scott, D.H.

1987-01-01

New geologic mapping of the Elysium volcanic province at 1:2,000,000 scale and crater counts provide a basis for describing its overall eruptive history. Four stages are listed and described in order of their relative age. They are also distinguished by eruption style and location. Stage 1: Central volcanism at Hecates and Albor Tholi. Stage 2: Shield and complex volcanism at Elysium Mons and Elysium Fossae. Stage 3: Rille volcanism at Elysium Fossae and Utopia Planitia. Stage 4: Flood lava and pyroclastic eruptions at Hecates Tholus and Elysium Mons. Tectonic and channeling activity in the Elysium region is intimately associated with volcanism. Recent work indicates that isostatic uplift of Tharsis, loading by Elysium Mons, and flexural uplift of the Elysium rise produced the stresses responsible for the fracturing and wrinkle-ridge formation in the region. Coeval faulting and channel formation almost certainly occurred in the pertinent areas in Stages 2 to 4. Older faults east of the lava flows and channels on Hecates Tholus may be coeval with Stage 1

Observations of volcanic plumes using small balloon soundings

Science.gov (United States)

Voemel, H.

2015-12-01

Eruptions of volcanoes are very difficult to predict and for practical purposes may occur at any time. Any observing system intending to observe volcanic eruptions has to be ready at any time. Due to transport time scales, emissions of large volcanic eruptions, in particular injections into the stratosphere, may be detected at locations far from the volcano within days to weeks after the eruption. These emissions may be observed using small balloon soundings at dedicated sites. Here we present observations of particles of the Icelandic Grimsvotn eruption at the Meteorological Observatory Lindenberg, Germany in the months following the eruption and observations of opportunity of other volcanic particle events. We also present observations of the emissions of SO2 from the Turrialba volcano at San Jose, Costa Rica. We argue that dedicated sites for routine observations of the clean and perturbed atmosphere using small sounding balloons are an important element in the detection and quantification of emissions from future volcanic eruptions.

The Role of Volcanic Activity in Climate and Global Change

KAUST Repository

Stenchikov, Georgiy L.

2015-09-23

Explosive volcanic eruptions are magnificent events that in many ways affect the Earth\\'s natural processes and climate. They cause sporadic perturbations of the planet\\'s energy balance, activating complex climate feedbacks and providing unique opportunities to better quantify those processes. We know that explosive eruptions cause cooling in the atmosphere for a few years, but we have just recently realized that volcanic signals can be seen in the subsurface ocean for decades. The volcanic forcing of the previous two centuries offsets the ocean heat uptake and diminishes global warming by about 30%. The explosive volcanism of the twenty-first century is unlikely to either cause any significant climate signal or to delay the pace of global warming. The recent interest in dynamic, microphysical, chemical, and climate impacts of volcanic eruptions is also excited by the fact that these impacts provide a natural analogue for climate geoengineering schemes involving deliberate development of an artificial aerosol layer in the lower stratosphere to counteract global warming. In this chapter we aim to discuss these recently discovered volcanic effects and specifically pay attention to how we can learn about the hidden Earth-system mechanisms activated by explosive volcanic eruptions. To demonstrate these effects we use our own model results when possible along with available observations, as well as review closely related recent publications.

The monogenetic Bayuda Volcanic Field, Sudan - New insights into geology and volcanic morphology

Science.gov (United States)

Lenhardt, Nils; Borah, Suranjana B.; Lenhardt, Sukanya Z.; Bumby, Adam J.; Ibinoof, Montasir A.; Salih, Salih A.

2018-05-01

The small monogenetic Bayuda Volcanic Field (BVF; 480 km2), comprising at least 53 cinder cones and 15 maar volcanoes in the Bayuda desert of northern Sudan is one of a few barely studied volcanic occurrences of Quaternary age in Sudan. The exact age of the BVF and the duration of volcanic activity has not yet been determined. Furthermore, not much is known about the eruptional mechanisms and the related magmatic and tectonic processes that led to the formation of the volcanic field. In the framework of a larger project focusing on these points it is the purpose of this contribution to provide a first account of the general geology of the BVF volcanoes as well as a first description of a general stratigraphy, including a first description of their morphological characteristics. This was done by means of fieldwork, including detailed rock descriptions, as well as the analysis of satellite images (SRTM dataset at 30 m spatial resolution). The BVF cinder cones are dominated by scoracious lapilli tephra units, emplaced mainly by pyroclastic fallout from Strombolian eruptions. Many cones are breached and are associated with lava flows. The subordinate phreatomagmatism represented by maar volcanoes suggests the presence of ground and/or shallow surface water during some of the eruptions. The deposits constituting the rims around the maar volcanoes are interpreted as having mostly formed due to pyroclastic surges. Many of the tephra rings around the maars are underlain by thick older lava flows. These are inferred to be the horizons where rising magma interacted with groundwater. The existence of phreatomagmatic deposits may point to a time of eruptive activity during a phase with wetter conditions and therefore higher groundwater levels than those encountered historically. This is supported by field observations as well as the morphological analysis, providing evidence for relatively high degrees of alteration of the BVF volcanoes and therefore older eruption ages as

Critical review of a new volcanic eruption chronology

Science.gov (United States)

Neuhäuser, Dagmar L.; Neuhäuser, Ralph

2016-04-01

Sigl. et al. (2015, Nature) present historical evidence for 32 volcanic eruptions to evaluate their new polar ice core 10-Be chronology - 24 are dated within three years of sulfur layers in polar ice. Most of them can be interpreted as weather phenomena (Babylonia: disk of sun like moon, reported for only one day, e.g. extinction due to clouds), Chinese sunspot reports (pellet, black vapor, etc.), solar eclipses, normal ice-halos and coronae (ring, bow, etc.), one aurora (redness), red suns due to mist drops in wet fog or fire-smoke, etc. Volcanic dust may facilitate detections of sunspots and formation of Bishop's ring, but tend to inhibit ice-halos, which are otherwise often reported in chronicles. We are left with three reports possibly indicating volcanic eruptions, namely fulfilling genuine criteria for atmospheric disturbances due to volcanic dust, e.g. bluish or faint sun, orange sky, or fainting of stars for months (BCE 208, 44-42, and 32). Among the volcanic eruptions used to fix the chronology (CE 536, 626, 939, 1257), the reports cited for the 930s deal only with 1-2 days, at least one reports an eclipse. In the new chronology, there is a sulfur detection eight years after the Vesuvius eruption, but none in CE 79. It may appear surprising that, from BCE 500 to 1, all five northern sulfur peaks labeled in figure 2 in Sigl et al. are systematically later by 2-4 years than the (corresponding?) southern peaks, while all five southern peaks from CE 100 to 600 labeled in figure 2 are systematically later by 1-4 years than the (corresponding?) northern peaks. Furthermore, in most of their six strongest volcanic eruptions, temperatures decreased years before their sulfur dating - correlated with weak solar activity as seen in radiocarbon, so that volcanic climate forcing appears dubious here. Also, their 10-Be peaks at CE 775 and 994 are neither significant nor certain in dating.

Effects of Volcanic Eruptions on Stratospheric Ozone Recovery

Science.gov (United States)

Rosenfield, Joan E.

2002-01-01

The effects of the stratospheric sulfate aerosol layer associated with the Mt. Pinatubo volcano and future volcanic eruptions on the recovery of the ozone layer is studied with an interactive two-dimensional photochemical model. The time varying chlorine loading and the stratospheric cooling due to increasing carbon dioxide have been taken into account. The computed ozone and temperature changes associated with the Mt. Pinatubo eruption in 1991 agree well with observations. Long model runs out to the year 2050 have been carried out, in which volcanoes having the characteristics of the Mount Pinatubo volcano were erupted in the model at 10-year intervals starting in the year 2010. Compared to a non-volcanic run using background aerosol loading, transient reductions of globally averaged column ozone of 2-3 percent were computed as a result of each of these eruptions, with the ozone recovering to that computed for the non-volcanic case in about 5 years after the eruption. Computed springtime Arctic column ozone losses of from 10 to 18 percent also recovered to the non-volcanic case within 5 years. These results suggest that the long-term recovery of ozone would not be strongly affected by infrequent volcanic eruptions with a sulfur loading approximating Mt. Pinatubo. Sensitivity studies in which the Arctic lower stratosphere was forced to be 4 K and 10 K colder resulted in transient ozone losses of which also recovered to the non-volcanic case in 5 years. A case in which a volcano five times Mt. Pinatubo was erupted in the year 2010 led to maximum springtime column ozone losses of 45 percent which took 10 years to recover to the background case. Finally, in order to simulate a situation in which frequent smaller volcanic eruptions result in increasing the background sulfate loading, a simulation was made in which the background aerosol was increased by 10 percent per year. This resulted in a delay of the recovery of column ozone to 1980 values of more than 10 years.

Volcanic Ash Data Assimilation System for Atmospheric Transport Model

Science.gov (United States)

Ishii, K.; Shimbori, T.; Sato, E.; Tokumoto, T.; Hayashi, Y.; Hashimoto, A.

2017-12-01

The Japan Meteorological Agency (JMA) has two operations for volcanic ash forecasts, which are Volcanic Ash Fall Forecast (VAFF) and Volcanic Ash Advisory (VAA). In these operations, the forecasts are calculated by atmospheric transport models including the advection process, the turbulent diffusion process, the gravitational fall process and the deposition process (wet/dry). The initial distribution of volcanic ash in the models is the most important but uncertain factor. In operations, the model of Suzuki (1983) with many empirical assumptions is adopted to the initial distribution. This adversely affects the reconstruction of actual eruption plumes.We are developing a volcanic ash data assimilation system using weather radars and meteorological satellite observation, in order to improve the initial distribution of the atmospheric transport models. Our data assimilation system is based on the three-dimensional variational data assimilation method (3D-Var). Analysis variables are ash concentration and size distribution parameters which are mutually independent. The radar observation is expected to provide three-dimensional parameters such as ash concentration and parameters of ash particle size distribution. On the other hand, the satellite observation is anticipated to provide two-dimensional parameters of ash clouds such as mass loading, top height and particle effective radius. In this study, we estimate the thickness of ash clouds using vertical wind shear of JMA numerical weather prediction, and apply for the volcanic ash data assimilation system.

Volcanic risk perception of young people in the urban areas of Vesuvius: Comparisons with other volcanic areas and implications for emergency management

Science.gov (United States)

Carlino, S.; Somma, R.; Mayberry, G.C.

2008-01-01

More than 600 000 people are exposed to volcanic risk in the urban areas near the volcano, Vesuvius, and may need to be evacuated if there is renewed volcanic activity. The success of a future evacuation will strongly depend on the level of risk perception and preparedness of the at-risk communities during the current period of quiescence. The volcanic risk perception and preparedness of young people is of particular importance because hazard education programs in schools have been shown to increase the clarity of risk perception and students often share their knowledge with their parents. In order to evaluate young people's risk perception and preparedness for a volcanic crisis, a multiple choice questionnaire was distributed to 400 high-school students in three municipalities located close to the volcano. The overall results suggest that despite a 60-year period of quiescence at Vesuvius, the interviewed students have an accurate perception of the level of volcanic risk. On the other hand, the respondents demonstrate a clear lack of understanding of volcanic processes and their related hazards. Also, the interviewed students show high levels of fear, poor perceived ability to protect themselves from the effects of a future eruption, and insufficient knowledge of the National Emergency Plan for Vesuvian Area (NEPVA). The latter result suggests that in comparison with volcanic crises in other regions, during a future eruption of Vesuvius, there may not be enough time to educate the large number of people living near the volcano about how to appropriately respond. The inadequate risk education and preparedness of respondents implies that a strong effort is needed to improve communication strategies in order to facilitate successful evacuations. Therefore, it is important to take advantage of the present period of quiescence at Vesuvius to improve the accuracy of risk perception of youth in local communities. ?? 2008.

Pacific seamount volcanism in space and time

Science.gov (United States)

Hillier, J. K.

2007-02-01

Seamounts constitute some of the most direct evidence about intraplate volcanism. As such, when seamounts formed and into which tectonic setting they erupted (i.e. on-ridge or off-ridge) are a useful reflection of how the properties of the lithosphere interact with magma generation in the fluid mantle beneath. Proportionately few seamounts are radiometrically dated however, and these tend to be recently active. In order to more representatively sample and better understand Pacific seamount volcanism this paper estimates the eruption ages (tvolc) of 2706 volcanoes via automated estimates of lithospheric strength. Lithospheric strength (GTRrel) is deduced from the ratio of gravity to topography above the summits of volcanoes, and is shown to correlate with seafloor age at the time of volcanic loading (Δt) at 61 sites where radiometric constraints upon Δt exist. A trend of fits data for these 61, and with seafloor age (tsf) known, can date the 2706 volcanoes; tvolc = tsf - Δt. Widespread recurrences of volcanism proximal to older features (e.g. the Cook-Austral alignment in French Polynesia) suggest that the lithosphere exerts a significant element of control upon the location of volcanism, and that magmatic throughput leaves the lithosphere more susceptible to the passage of future melts. Observations also prompt speculation that: the Tavara seamounts share morphological characteristics and isostatic compensation state with the Musicians, and probably formed similarly; the Easter Island chain may be a modern analogy to the Cross-Lines; a Musicians - South Hawaiian seamounts alignment may be deflecting the Hawaiian hotspot trace.

Stratigraphical sequence and geochronology of the volcanic rock series in caifang basin, south jiangxi

International Nuclear Information System (INIS)

Xu Xunsheng; Wu Jianhua

2010-01-01

The late Mesozoic volcanic rocks in Jiangxi constitute two volcanic belts: the northern is Xiajiang-Guangfeng volcanic belt, the volcanic rocks series belong to one volcano cycle and named Wuyi group which is subdivided into three formations (Shuangfengling formation, Ehuling formation and Shixi formation); the southern is Sannan-Xunwu volcanic belt, the volcanic rocks series in Caifang basin which locates on Sannan-Xunwu volcanic belt also belong to only one volcano cycle. It can be subdivided into two lithology and lithofacies units (upper and lower): the lower unit consists of sedimentary rocks and associated with a subordinate amount of volcanic rocks, it belongs to erupt-deposit facies which is the product of early volcanic stage; the upper unit is mostly composed of volcanic rocks, it belongs to erupt facies that is the volcanic eruption product. SHRIMP zircon U-Pb age of rhyolite? which locates at the top of the upper unit is 130.79 ± 0.73) Ma. According to the new International Stratigraphic Chart, the boundary of Jurassic and Cretaceous is (145.4 ± 4.0) Ma, so the age shows that the geologic period of Caifang volcanic rocks series is early Early Cretaceous epoch. On the basis of lithological correlation, lithofacies and stratigraphic horizon analysis, the volcanic rock series in Caifang basin fall under Wuyi group, and the lower unit could be incorporated into Shuangfengling formation, the upper unit could be incorporated into Ehuling formation. The subdivision of sequence and the determination of geochronology of the volcanic rock series in Caifang basin provide some references for the study of the late Mesozoic volcanic rocks series of the Sannan-Xunwu volcanic belt. (authors)

Volcanism at 1.45 Ma within the Yellowstone Volcanic Field, United States

Science.gov (United States)

Rivera, Tiffany A.; Furlong, Ryan; Vincent, Jaime; Gardiner, Stephanie; Jicha, Brian R.; Schmitz, Mark D.; Lippert, Peter C.

2018-05-01

Rhyolitic volcanism in the Yellowstone Volcanic Field has spanned over two million years and consisted of both explosive caldera-forming eruptions and smaller effusive flows and domes. Effusive eruptions have been documented preceding and following caldera-forming eruptions, however the temporal and petrogenetic relationships of these magmas to the caldera-forming eruptions are relatively unknown. Here we present new 40Ar/39Ar dates for four small-volume eruptions located on the western rim of the second-cycle caldera, the source of the 1.300 ± 0.001 Ma Mesa Falls Tuff. We supplement our new eruption ages with whole rock major and trace element chemistry, Pb isotopic ratios of feldspar, and paleomagnetic and rock magnetic analyses. Eruption ages for the effusive Green Canyon Flow (1.299 ± 0.002 Ma) and Moonshine Mountain Dome (1.302 ± 0.003 Ma) are in close temporal proximity to the eruption age of the Mesa Falls Tuff. In contrast, our results indicate a period of volcanism at ca 1.45 Ma within the Yellowstone Volcanic Field, including the eruption of the Bishop Mountain Flow (1.458 ± 0.002 Ma) and Tuff of Lyle Spring (1.450 ± 0.003 Ma). These high-silica rhyolites are chemically and isotopically distinct from the Mesa Falls Tuff and related 1.3 Ma effusive eruptions. The 40Ar/39Ar data from the Tuff of Lyle Spring demonstrate significant antecrystic inheritance, prevalent within the upper welded ash-flow tuff matrix, and minimal within individual pumice. Antecrysts are up to 20 kyr older than the eruption, with subpopulations of grains occurring every few thousand years. We interpret these results as an indicator for the timing of magmatic pulses into a growing magmatic system that would ultimately erupt the Tuff of Lyle Spring, and which we more broadly interpret as the tempo of crustal accumulation associated with bimodal magmatism. We propose a system whereby chemically, isotopically, and temporally distinct, isolated small-volume magma batches are

PICASSO, COUPP and PICO - search for dark matter with bubble chambers

Directory of Open Access Journals (Sweden)

Amole C.

2015-01-01

Full Text Available The PICASSO and COUPP collaborations use superheated liquid detectors to search for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs. These experiments, located in the underground laboratory of SNOLAB, Canada, detect phase transitions triggered by nuclear recoils in the keV range induced by interactions with WIMPs. We present details of the construction and operation of these detectors as well as the results, obtained by several years of observations. We also introduce PICO, a joint effort of the two collaborations to build a second generation ton-scale bubble chamber with 250 liters of active liquid.

The Te Rere and Okareka eruptive episodes : Okataina Volcanic Centre, Taupo Volcanic Zone, New Zealand

International Nuclear Information System (INIS)

Nairn, I.A.

1992-01-01

The Te Rere and Okareka eruptive episodes occurred within the Okataina Volcanic Centre at c. 21 000 and 18 000 yr B.P., respectively. The widespread rhyolitic pumice fall deposits of Te Rere Ash (volume 5 km 3 ) and Okareka Ash (6 km 3 ) are only rarely exposed in near-source areas, and locations of their vent areas have been uncertain. New exposures and petrographic and chemical analyses show that the Te Rere episode eruptions occurred from multiple vents, up to 20 km apart, on the Haroharo linear vent zone. The Okareka episode eruptions occurred from vents since buried beneath the Tarawera volcanic massif. Eruption of the rhyolitic Okareka pumice fall was immediately preceded by a small basaltic scoria eruption, apparently from vents close to those for the following rhyolite eruptions. Dacitic mixed pumices scattered within the rhyolite pumice layers immediately overlying the scoria were formed by mixing of the basalt and rhyolite magmas. The Te Rere and Okareka pyroclastic eruptions were both followed by extrusion of voluminous rhyolite lavas. These eruptive episodes mark the commencement of growth of the present-day Haroharo and Tarawera volcanic complexes. (author). 27 refs., 14 figs., 6 tabs

Volcanic Rocks and Features

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Volcanoes have contributed significantly to the formation of the surface of our planet. Volcanism produced the crust we live on and most of the air we breathe. The...

Volcanic ash as fertiliser for the surface ocean

Directory of Open Access Journals (Sweden)

B. Langmann

2010-04-01

Full Text Available Iron is a key limiting micro-nutrient for marine primary productivity. It can be supplied to the ocean by atmospheric dust deposition. Volcanic ash deposition into the ocean represents another external and so far largely neglected source of iron. This study demonstrates strong evidence for natural fertilisation in the iron-limited oceanic area of the NE Pacific, induced by volcanic ash from the eruption of Kasatochi volcano in August 2008. Atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom in the NE Pacific Ocean which for the first time strongly suggests a connection between oceanic iron-fertilisation and volcanic ash supply.

Ampliación del ámbito geográfico-altitudinal y uso de hábitats suburbanos por la mascarita pico grueso (Geothlypis poliocephala Geographic-altitudinal range extension and suburban habitat use of the Grey-crowned Yellowthroat (Geothlypis poliocephala

Directory of Open Access Journals (Sweden)

Ian MacGregor-Fors

2008-12-01

Full Text Available Se presenta el primer registro de la mascarita pico grueso (Geothlypis poliocephala para la región del Eje Neovolcánico Transversal, México. Los sitios donde registramos/capturamos esta especie se encuentran en los suburbios de la ciudad de Morelia, 427 m arriba del ámbito altitudinal descrito para la especie. Esto puede deberse a 2 factores: 1 la urbanización que genera hábitats propicios para la especie en su periferia, y 2 el incremento de la temperatura en la región en la que se encuentra la ciudad de Morelia. Ambos factores facilitan que esta especie de tierras bajas pueda habitar en áreas de mayor altitud. Así, nuestros registros sugieren que la mascarita pico grueso puede catalogarse como especie potencial a utilizar hábitats suburbanos cuando éstos son similares a los hábitats en los que se distribuye de manera natural.The first record of the Grey-crowned Yellowthroat (Geothlypis poliocephala in the Transmexican Volcanic Belt biogeographic region (Mexico, within the Morelia city suburbs is presented. Sites were this parulid was sighted / captured were located 427 m higher than its described altitudinal range. This could be due to 2 factors: 1 urbanization generates suitable habitats for this species in periurban areas, and 2 temperature values have increased in the region where the city of Morelia is located. These factors allow that a lowland bird species can inhabit in more elevated areas. Thus, our records suggest that the Grey-crowned Yellowthroat can be catalogued as potential to use suburban environments when these are similar to those used by the species on its natural distribution area.

Geochemical evidence for waning magmatism and polycyclic volcanism at Crater Flat, Nevada

International Nuclear Information System (INIS)

Perry, F.V.; Crowe, B.M.

1992-01-01

This paper reports that petrologic and geochemical studies of basaltic rocks in the Yucca Mountain region are currently focused on understanding the evolution of volcanism in the Crater Flat volcanic field and the mechanisms of polycyclic volcanic field and the mechanisms of polycyclic volcanism at the Lathrop Wells volcanic center, the youngest center in the Crater Flat volcanic field. Geochemical and petrologic data indicate that the magma chambers which supplied the volcanic centers at Crater Flat became situated at greater crustal depths as the field evolved. Deep magma chambers may be related to a waning magma flux that was unable to sustain upper crustal magma conduits and chambers. Geochemical data from the Lathrop Wells volcanic center indicate that eruptive units identified from field and geomorphic relationships are geochemically distinct. The geochemical variations cannot be explained by fractional crystallization of a single magma batch, indicating that several magma batches were involved in the formation of the Lathrop Wells center. Considering the low magma flux in the Yucca Mountain region in the Quaternary, the probability of several magma batches erupting essentially simultaneously at Lathrop Wells is considered remote

Marine litter on the seafloor of the Faial-Pico Passage, Azores Archipelago.

Science.gov (United States)

Rodríguez, Yasmina; Pham, Christopher K

2017-03-15

Plastic pollution in the marine environment attracts much attention from both researchers and the general public. Plastic items and other debris are commonly observed everywhere in the ocean, from the surface down to the deep ocean floor. In this study, we analysed 45.2km of video footage, collected during 56 transects surveying the seafloor of the Faial-Pico Passage in order to quantify the abundance of marine litter and its interactions with benthic fauna. The footage was collected by a Remotely Operated Vehicle (ROV) and a manned submersible at depths ranging between 40 and 525m. The mean litter density in the passage was 0.26±0.03 items·100m -1 (±SE) and was significantly higher between 151 and 250m compared to other depth strata. Overall, derelict fishing gear, mostly made of plastic, were the most common objects found on the seafloor, representing 64% of all items. Although we observed few evidence of direct deleterious effects by the litter, interactions with fauna were observed in more than half of the items. This study makes an important contribution in quantifying the abundance of marine litter on the seafloor of the Azores. The location of the Faial-Pico Passage, close to shore, makes it an appropriate site for long-term monitoring of litter on the seafloor and evaluate the efficiency of upcoming public policies aimed at reducing litter input into the oceans. Copyright © 2017 Elsevier Ltd. All rights reserved.

What, When, Where, and Why of Secondary Hawaiian Hotspot Volcanism

Science.gov (United States)

Garcia, M. O.; Ito, G.; Applegate, B.; Weis, D.; Swinnard, L.; Flinders, A.; Hanano, D.; Nobre-Silva, I.; Bianco, T.; Naumann, T.; Geist, D.; Blay, C.; Sciaroni, L.; Maerschalk, C.; Harpp, K.; Christensen, B.

2007-12-01

Secondary hotspot volcanism occurs on most oceanic island groups (Hawaii, Canary, Society) but its origins remain enigmatic. A 28-day marine expedition used multibeam bathymetry and acoustic imagery to map the extent of submarine volcanic fields around the northern Hawaiian Islands (Kauai, Niihau and Kaula), and the JASON2 ROV to sample many volcanoes to characterize the petrology, geochemistry (major and trace elements, and isotopes) and ages of the lavas from these volcanoes. Our integrated geological, geochemical and geophysical study attempts to examine the what (compositions and source), where (distribution and volumes), when (ages), and why (mechanisms) of secondary volcanism on and around the northern Hawaiian Islands. A first-order objective was to establish how the submarine volcanism relates in space, time, volume, and composition to the nearby shield volcanoes and their associated onshore secondary volcanism. Our surveying and sampling revealed major fields of submarine volcanoes extending from the shallow slopes of these islands to more than 100 km offshore. These discoveries dramatically expand the volumetric importance, distribution and geodynamic framework for Hawaiian secondary volcanism. New maps and rock petrology on the samples collected will be used to evaluate currently proposed mechanisms for secondary volcanism and to consider new models such as small-scale mantle convection driven by thermal and melt-induced buoyancy to produce the huge volume of newly discovered lava. Our results seem to indicate substantial revisions are needed to our current perceptions of hotspot dynamics for Hawaii and possibly elsewhere.

Impacto del entrenamiento en consejería nutricional al profesional de la salud en el desempeño de la atención en niños menores de dos años en el centro materno infantil Tambo Viejo

OpenAIRE

Rivas Rivadeneira, Juana Edith

2017-01-01

La consejería nutricional es un procedimiento con la finalidad de fomentar prácticas que promuevan un crecimiento y desarrollo adecuado a los niños desde los primeros días con el fin de evitar una inadecuada alimentación. El objetivo es determinar el impacto del entrenamiento en consejería nutricional al profesional de la salud en el desempeño de la atención en niños menores de dos años en el Centro Materno Infantil Tambo Viejo. Materiales y métodos: Estudio cuasi experimental, prospectivo...

Volcanic air pollution hazards in Hawaii

Science.gov (United States)

Elias, Tamar; Sutton, A. Jeff

2017-04-20

Noxious sulfur dioxide gas and other air pollutants emitted from Kīlauea Volcano on the Island of Hawai‘i react with oxygen, atmospheric moisture, and sunlight to produce volcanic smog (vog) and acid rain. Vog can negatively affect human health and agriculture, and acid rain can contaminate household water supplies by leaching metals from building and plumbing materials in rooftop rainwater-catchment systems. U.S. Geological Survey scientists, along with health professionals and local government officials are working together to better understand volcanic air pollution and to enhance public awareness of this hazard.

Volcanic unrest and hazard communication in Long Valley Volcanic Region, California

Science.gov (United States)

Hill, David P.; Mangan, Margaret T.; McNutt, Stephen R.

2017-01-01

The onset of volcanic unrest in Long Valley Caldera, California, in 1980 and the subsequent fluctuations in unrest levels through May 2016 illustrate: (1) the evolving relations between scientists monitoring the unrest and studying the underlying tectonic/magmatic processes and their implications for geologic hazards, and (2) the challenges in communicating the significance of the hazards to the public and civil authorities in a mountain resort setting. Circumstances special to this case include (1) the sensitivity of an isolated resort area to media hype of potential high-impact volcanic and earthquake hazards and its impact on potential recreational visitors and the local economy, (2) a small permanent population (~8000), which facilitates face-to-face communication between scientists monitoring the hazard, civil authorities, and the public, and (3) the relatively frequent turnover of people in positions of civil authority, which requires a continuing education effort on the nature of caldera unrest and related hazards. Because of delays associated with communication protocols between the State and Federal governments during the onset of unrest, local civil authorities and the public first learned that the U.S. Geological Survey was about to release a notice of potential volcanic hazards associated with earthquake activity and 25-cm uplift of the resurgent dome in the center of the caldera through an article in the Los Angeles Times published in May 1982. The immediate reaction was outrage and denial. Gradual acceptance that the hazard was real required over a decade of frequent meetings between scientists and civil authorities together with public presentations underscored by frequently felt earthquakes and the onset of magmatic CO2 emissions in 1990 following a 11-month long earthquake swarm beneath Mammoth Mountain on the southwest rim of the caldera. Four fatalities, one on 24 May 1998 and three on 6 April 2006, underscored the hazard posed by the CO2�

Magnetic properties of frictional volcanic materials

Science.gov (United States)

Kendrick, Jackie E.; Lavallée, Yan; Biggin, Andrew; Ferk, Annika; Leonhardt, Roman

2015-04-01

During dome-building volcanic eruptions, highly viscous magma extends through the upper conduit in a solid-like state. The outer margins of the magma column accommodate the majority of the strain, while the bulk of the magma is able to extrude, largely undeformed, to produce magma spines. Spine extrusion is often characterised by the emission of repetitive seismicity, produced in the upper <1 km by magma failure and slip at the conduit margins. The rheology of the magma controls the depth at which fracture can occur, while the frictional properties of the magma are important in controlling subsequent marginal slip processes. Upon extrusion, spines are coated by a carapace of volcanic fault rocks which provide insights into the deeper conduit processes. Frictional samples from magma spines at Mount St. Helens (USA), Soufriere Hills (Montserrat) and Mount Unzen (Japan) have been examined using structural, thermal and magnetic analyses to reveal a history of comminution, frictional heating, melting and cooling to form volcanic pseudotachylyte. Pseudotachylyte has rarely been noted in volcanic materials, and the recent observation of its syn-eruptive formation in dome-building volcanoes was unprecedented. The uniquely high thermal conditions of volcanic environments means that frictional melt remains at elevated temperatures for longer than usual, causing slow crystallisation, preventing the development of some signature "quench" characteristics. As such, rock-magnetic tests have proven to be some of the most useful tools in distinguishing pseudotachylytes from their andesite/ dacite hosts. In volcanic pseudotachylyte the mass normalised natural remanent magnetisation (NRM) when further normalised with the concentration dependent saturation remanence (Mrs) was found to be higher than the host rock. Remanence carriers are defined as low coercive materials across all samples, and while the remanence of the host rock displays similarities to an anhysteretic remanent

DIREITO AGRÁRIO E O TRATAMENTO DOS CONTRATOS AGRÁRIOS ATÍPICOS

OpenAIRE

Fabrício Pinto Weiblen; Marcelo Scherer da Silva; Tarso Wayhs Tech; José Fernando Lutz Coelho

2012-01-01

Aborda a necessidade de um tratamento adequado e diferenciado aos contratos agrários atípicos em face das complexas relações que se desenvolvem no meio rural atualmente. Apresenta ainda uma visão crítica a respeito das características e aplicabilidade da legislação agrária no cenário jurídico e propõe alternativas com o objetivo de uma prestação mais eficiente do Direito Agrário na área contratual.

SYSTHESIS OF VOLCANISM STUDIES FOR THE YUCCA MOUNTAIN SITE CHARACTERIZATION PROJECT

Energy Technology Data Exchange (ETDEWEB)

Perry, F. V.; Crowe, G. A.; Valentine, G. A.; Bowker, L. M.

1997-09-23

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The hazard of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt (<5 Ma). The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. The age of the Lathrop Wells center is now confidently determined to be about 75 thousand years old. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. The distribution of Pliocene and Quaternary basaltic volcanic centers is evaluated with respect to tectonic models for detachment, caldera, regional and local rifting, and the Walker Lane structural zone. Geophysical data are described for the YMR and are used as an aid to understand the distribution of past basaltic volcanic centers and possible future magmatic processes. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the

Petrogenesis of volcanic rocks that host the world-class Agsbnd Pb Navidad District, North Patagonian Massif: Comparison with the Jurassic Chon Aike Volcanic Province of Patagonia, Argentina

Science.gov (United States)

Bouhier, Verónica E.; Franchini, Marta B.; Caffe, Pablo J.; Maydagán, Laura; Rapela, Carlos W.; Paolini, Marcelo

2017-05-01

We present the first study of the volcanic rocks of the Cañadón Asfalto Formation that host the Navidad world-class Ag + Pb epithermal district located in the North Patagonian Massif, Patagonia, Argentina. These volcanic and sedimentary rocks were deposited in a lacustrine environment during an extensional tectonic regime associated with the breakup of Gondwana and represent the mafic to intermediate counterparts of the mainly silicic Jurassic Chon Aike Volcanic Province. Lava flows surrounded by autobrecciated carapace were extruded in subaerial conditions, whereas hyaloclastite and peperite facies suggest contemporaneous subaqueous volcanism and sedimentation. LA-ICPMS Usbnd Pb ages of zircon crystals from the volcanic units yielded Middle Jurassic ages of 173.9 ± 1.9 Ma and 170.8 ± 3 Ma. In the Navidad district, volcanic rocks of the Cañadón Asfalto Formation show arc-like signatures including high-K basaltic-andesite to high-K dacite compositions, Rb, Ba and Th enrichment relative to the less mobile HFS elements (Nb, Ta), enrichment in light rare earth elements (LREE), Ysbnd Ti depletion, and high Zr contents. These characteristics could be explained by assimilation of crustal rocks in the Jurassic magmas, which is also supported by the presence of zircon xenocrysts with Permian and Middle-Upper Triassic ages (281.3 Ma, 246.5, 218.1, and 201.3 Ma) and quartz xenocrysts recognized in these volcanic units. Furthermore, Sr and Nd isotope compositions suggest a contribution of crustal components in these Middle Jurassic magmas. High-K basaltic andesite has initial 87Sr/86Sr ratios of 0.70416-0.70658 and ξNd(t) values of -5.3 and -4. High-K dacite and andesite have initial 87Sr/86Sr compositions of 0.70584-0.70601 and ξNd(t) values of -4,1 and -3,2. The range of Pb isotope values (206Pb/204Pb = 18.28-18.37, 207Pb/204Pb = 15.61-15.62, and 208Pb/204Pb = 38.26-38.43) of Navidad volcanic rocks and ore minerals suggest mixing Pb sources with contributions of

Atmospheric dispersion simulations of volcanic gas from Miyake Island by SPEEDI

International Nuclear Information System (INIS)

Nagai, Haruyasu; Furuno, Akiko; Terada, Hiroaki; Umeyama, Nobuaki; Yamazawa, Hiromi; Chino, Masamichi

2001-03-01

Japan Atomic Energy Research Institute is advancing the study for prediction of material circulation in the environment to cope with environmental pollution, based on SPEEDI (System for Prediction of Environmental Emergency Dose Information) and WSPEEDI (Worldwide version of SPEEDI), which are originally developed aiming at real-time prediction of atmospheric dispersion of radioactive substances accidentally released from nuclear facility. As a part of this study, dispersion simulation of volcanic gas erupted from Miyake Island is put into practice. After the stench incident at the west Kanto District on 28 August 2000 caused by volcanic gas from Miyake Island, the following simulations dealing with atmospheric dispersion of volcanic gas from Miyake Island have been carried out. (1) Retrospective simulation to analyze examine the mechanism of the transport of high concentration volcanic gas to the west Kanto District on 28 August and to estimate the release amount of volcanic gas. (2) Retrospective simulation to analyze the mechanism of the transport of volcanic gas to Tokai and Kansai districts in a case of stench incident on 13 September. (3) Automated real-time simulation from the acquisition of meteorological data to the output of figures for operational prediction of the transport of volcanic gas to Tokai and Kanto districts. This report describes the details of these studies. (author)

Volcanic hazards of North Island, New Zealand-overview

Science.gov (United States)

Dibble, R. R.; Nairn, I. A.; Neall, V. E.

1985-10-01

In October 1980, a National Civil Defence Planning Committee on Volcanic Hazards was formed in New Zealand, and solicited reports on the likely areas and types of future eruptions, the risk to public safety, and the need for special precautions. Reports for eight volcanic centres were received, and made available to the authors. This paper summarises and quantifies the type and frequency of hazard, the public risk, and the possibilities for mitigation at the 7 main volcanic centres: Northland, Auckland, White Island, Okataina, Taupo, Tongariro, and Egmont. On the basis of Recent tephrostratigraphy, eruption probabilities up to 20% per century (but commonly 5%), and tephra volumes up to 100 km 3 are credible.

Efecto de los inotrópicos sobre la mortalidad en falla cardiaca aguda. Metaanálisis en red de ensayos clínicos

OpenAIRE

Juan M. Sénior; Edison Muñoz; James Díaz

2017-01-01

Introducción: en pacientes con falla cardiaca aguda es necesario el uso de inotrópicos para lograr su estabilización. Objetivo: definir cuál de los medicamentos inotrópicos se asocia con menor mortalidad. Metodología: se realizó un metaanálisis en red con la aproximación frecuentista. La búsqueda sistemática incluyó PUBMED, EMBASE, CENTRAL, DARE, Epistemonikos, SieELO, LILACS y OpenGray. Se incluyeron ensayos clínicos con asignación aleatoria en pacientes con falla cardiaca aguda que re...

Geothermal and volcanism in west Java

Science.gov (United States)

Setiawan, I.; Indarto, S.; Sudarsono; Fauzi I, A.; Yuliyanti, A.; Lintjewas, L.; Alkausar, A.; Jakah

2018-02-01

Indonesian active volcanoes extend from Sumatra, Jawa, Bali, Lombok, Flores, North Sulawesi, and Halmahera. The volcanic arc hosts 276 volcanoes with 29 GWe of geothermal resources. Considering a wide distribution of geothermal potency, geothermal research is very important to be carried out especially to tackle high energy demand in Indonesia as an alternative energy sources aside from fossil fuel. Geothermal potency associated with volcanoes-hosted in West Java can be found in the West Java segment of Sunda Arc that is parallel with the subduction. The subduction of Indo-Australian oceanic plate beneath the Eurasian continental plate results in various volcanic products in a wide range of geochemical and mineralogical characteristics. The geochemical and mineralogical characteristics of volcanic and magmatic rocks associated with geothermal systems are ill-defined. Comprehensive study of geochemical signatures, mineralogical properties, and isotopes analysis might lead to the understanding of how large geothermal fields are found in West Java compared to ones in Central and East Java. The result can also provoke some valuable impacts on Java tectonic evolution and can suggest the key information for geothermal exploration enhancement.

Quantitative physical models of volcanic phenomena for hazards assessment of critical infrastructures

Science.gov (United States)

Costa, Antonio

2016-04-01

Volcanic hazards may have destructive effects on economy, transport, and natural environments at both local and regional scale. Hazardous phenomena include pyroclastic density currents, tephra fall, gas emissions, lava flows, debris flows and avalanches, and lahars. Volcanic hazards assessment is based on available information to characterize potential volcanic sources in the region of interest and to determine whether specific volcanic phenomena might reach a given site. Volcanic hazards assessment is focussed on estimating the distances that volcanic phenomena could travel from potential sources and their intensity at the considered site. Epistemic and aleatory uncertainties strongly affect the resulting hazards assessment. Within the context of critical infrastructures, volcanic eruptions are rare natural events that can create severe hazards. In addition to being rare events, evidence of many past volcanic eruptions is poorly preserved in the geologic record. The models used for describing the impact of volcanic phenomena generally represent a range of model complexities, from simplified physics based conceptual models to highly coupled thermo fluid dynamical approaches. Modelling approaches represent a hierarchy of complexity, which reflects increasing requirements for well characterized data in order to produce a broader range of output information. In selecting models for the hazard analysis related to a specific phenomenon, questions that need to be answered by the models must be carefully considered. Independently of the model, the final hazards assessment strongly depends on input derived from detailed volcanological investigations, such as mapping and stratigraphic correlations. For each phenomenon, an overview of currently available approaches for the evaluation of future hazards will be presented with the aim to provide a foundation for future work in developing an international consensus on volcanic hazards assessment methods.

Improving global detection of volcanic eruptions using the Ozone Monitoring Instrument (OMI

Directory of Open Access Journals (Sweden)

V. J. B. Flower

2016-11-01

Full Text Available Volcanic eruptions pose an ever-present threat to human populations around the globe, but many active volcanoes remain poorly monitored. In regions where ground-based monitoring is present the effects of volcanic eruptions can be moderated through observational alerts to both local populations and service providers, such as air traffic control. However, in regions where volcano monitoring is limited satellite-based remote sensing provides a global data source that can be utilised to provide near-real-time identification of volcanic activity. This paper details a volcanic plume detection method capable of identifying smaller eruptions than is currently feasible, which could potentially be incorporated into automated volcanic alert systems. This method utilises daily, global observations of sulfur dioxide (SO2 by the Ozone Monitoring Instrument (OMI on NASA's Aura satellite. Following identification and classification of known volcanic eruptions in 2005–2009, the OMI SO2 data, analysed using a logistic regression analysis, permitted the correct classification of volcanic events with an overall accuracy of over 80 %. Accurate volcanic plume identification was possible when lower-tropospheric SO2 loading exceeded ∼ 400 t. The accuracy and minimal user input requirements of the developed procedure provide a basis for incorporation into automated SO2 alert systems.

Volcanic Hazard Assessments for Nuclear Installations: Methods and Examples in Site Evaluation

International Nuclear Information System (INIS)

2016-07-01

To provide guidance on the protection of nuclear installations against the effects of volcanoes, the IAEA published in 2012 IAEA Safety Standards Series No. SSG-21, Volcanic Hazards in Site Evaluation for Nuclear Installations. SSG-21 addresses hazards relating to volcanic phenomena, and provides recommendations and general guidance for evaluation of these hazards. Unlike seismic hazard assessments, models for volcanic hazard assessment have not undergone decades of review, evaluation and testing for suitability in evaluating hazards at proposed nuclear installations. Currently in volcanology, scientific developments and detailed methodologies to model volcanic phenomena are evolving rapidly.This publication provides information on detailed methodologies and examples in the application of volcanic hazard assessment to site evaluation for nuclear installations, thereby addressing the recommendations in SSG-21. Although SSG-21 develops a logical framework for conducting a volcanic hazard assessment, this publication demonstrates the practicability of evaluating the recommendations in SSG-21 through a systematic volcanic hazard assessment and examples from Member States. The results of this hazard assessment can be used to derive the appropriate design bases and operational considerations for specific nuclear installations

The relational of Mesozoic volcanism to uranium mineralization in Guyuan-Hongshanzi area

International Nuclear Information System (INIS)

Wu Rengui; Xu Zhe; Yu Zhenqing; Jiang Shan; Shen Kefeng

2011-01-01

Based on the time of Mesozoic volcanism,the characteristic of major and trace element, and REE pattern of the volcanic rocks in Guyuan-Hongshanzi area, The Mesozoic volcanism can be divided into the early cycle and later cycle during the Early Cretaceous, and it's magma series is classified in two sub-series, one is alkaline series of trachyte dominated and another is subalkaline series of rhyolite dominated. The relations between Mesozoic volcanism and uranium mineralization is mainly shown in four aspects: (1) Uranium mineralization controlled by the coexist of two magma series; (2) Uranium mineralization controlled by superhypabyssal porphyry body in later cycle volcanism during the Early Cretaceous; (3) The porphyry body close to uranium mineralization,bearing the genesis characteristics of crust-mantle action; and (4) High Si and K content in the chemical composition of the mineralization volcanic rocks. (authors)

Role of volcanic forcing on future global carbon cycle

Directory of Open Access Journals (Sweden)

J. F. Tjiputra

2011-06-01

Full Text Available Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with a business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller eruptions similar to Pinatubo in amplitude, but set to occur frequently, would have a stronger impact on future climate change. In a scenario where the volcanic external forcings are prescribed with a five-year frequency, the induced cooling immediately lower the global temperature by more than one degree before it returns to the warming trend. Therefore, the climate change is approximately delayed by several decades, and by the end of the 21st century, the warming is still below two degrees when compared to the present day period. Our climate-carbon feedback analysis shows that future volcanic eruptions induce positive feedbacks (i.e., more carbon sink on both the terrestrial and oceanic carbon cycle. The feedback signal on the ocean is consistently smaller than the terrestrial counterpart and the feedback strength is proportionally related to the frequency of the volcanic eruption events. The cooler climate reduces the terrestrial heterotrophic respiration in the northern high latitude and increases net primary production in the tropics, which contributes to more than 45 % increase in accumulated carbon uptake over land. The increased solubility of CO₂ gas in seawater associated with cooler SST is offset by a reduced CO₂ partial pressure gradient between the ocean and the atmosphere, which results in small changes in net ocean carbon uptake. Similarly, there is nearly no change in the seawater buffer capacity simulated between the different volcanic scenarios. Our study shows that even

Contratos atípicos de las entidades descentralizadas del orden nacional sometidas al estatuto general de contratación de la administración pública

OpenAIRE

Ronderos Botero, Jorge Arturo

2012-01-01

La investigación aborda la problemática del contrato estatal atípico a partir de un marco teórico, con el fin de encontrar los contratos estales atípicos en la práctica pública, y a partir de allí realizar un análisis de su contenido de acuerdo al Estatuto General de Contratación de la Administración Pública.

Lunar cryptomaria: Physical characteristics, distribution, and implications for ancient volcanism

Science.gov (United States)

Whitten, Jennifer L.; Head, James W.

2015-02-01

Cryptomaria, lunar volcanic deposits obscured by crater and basin impact ejecta, can provide important information about the thermal and volcanic history of the Moon. The timing of cryptomare deposition has implications for the duration and flux of mare basalt volcanism. In addition, knowing the distribution of cryptomaria can provide information about mantle convection and lunar magma ocean solidification. Here we use multiple datasets (e.g., M3, LOLA, LROC, Diviner) to undertake a global analysis to identify the general characteristics (e.g., topography, surface roughness, rock abundance, albedo, etc.) of lunar light plains in order to better distinguish between ancient volcanic deposits (cryptomaria) and impact basin and crater ejecta deposits. We find 20 discrete regions of cryptomaria, covering approximately 2% of the Moon, which increase the total area covered by mare volcanism to 18% of the lunar surface. Comparisons of light plains deposits indicate that the two deposit types (volcanic and impact-produced) are best distinguished by mineralogic data. On the basis of cryptomaria locations, the distribution of mare volcanism does not appear to have changed in the time prior to its exposed mare basalt distribution. There are several hypotheses explaining the distribution of mare basalts, which include the influence of crustal thickness, mantle convection patterns, asymmetric distribution of source regions, KREEP distribution, and the influence of a proposed Procellarum impact basin. The paucity of farside mare basalts means that multiple factors, such as crustal thickness variations and mantle convection, are likely to play a role in mare basalt emplacement.

Backprojection of volcanic tremor

Science.gov (United States)

Haney, Matthew M.

2014-01-01

Backprojection has become a powerful tool for imaging the rupture process of global earthquakes. We demonstrate the ability of backprojection to illuminate and track volcanic sources as well. We apply the method to the seismic network from Okmok Volcano, Alaska, at the time of an escalation in tremor during the 2008 eruption. Although we are able to focus the wavefield close to the location of the active cone, the network array response lacks sufficient resolution to reveal kilometer-scale changes in tremor location. By deconvolving the response in successive backprojection images, we enhance resolution and find that the tremor source moved toward an intracaldera lake prior to its escalation. The increased tremor therefore resulted from magma-water interaction, in agreement with the overall phreatomagmatic character of the eruption. Imaging of eruption tremor shows that time reversal methods, such as backprojection, can provide new insights into the temporal evolution of volcanic sources.

A Manifestação de Tópico e Foco em Línguas da Família Tupi-Guarani

Directory of Open Access Journals (Sweden)

Marcia Maria Damaso VIEIRA

2014-01-01

Full Text Available Neste artigo, temos como objetivo identificar e descrever algumas construções envolvendo tópico e foco em duas línguas da família Tupi-Guarani: Asurini do Trocará e Tupinambá. Com base na abordagem cartográfica de Rizzi (1997,2004 para a periferia esquerda da oração, forneceremos evidências para a manifestação de diferentes tipos de categorias discursivas, como tópico com deslocamento para a esquerda e foco nas construções conhecidas como Indicativo II. Com a fi nalidade de enriquecer o nosso trabalho, resgatamos a análise de Rodrigues (1990 sobre um determinado tipo de foco verifi cado em Tupinambá que apresenta comportamento semelhante ao sistema de obviation encontrado nas línguas algonquinas.

Soporte nutricional adaptado al tratamiento fisioterápico de lesiones en el deporte

OpenAIRE

Sancho Morante, Alicia

2014-01-01

RESUMEN: INTRODUCCIÓN: En el abordaje de las lesiones, el tratamiento tanto médico como fisioterápico han sido ampliamente estudiados y conforman un elemento indispensable. Sin embargo, el soporte nutricional es un aspecto que, aunque recientemente se está demostrando que ofrece grandes beneficios, generalmente pasa a un segundo plano y no se le da la trascendencia que merece. OBJETIVOS: Relacionar la importancia que ejerce el consumo de determinados nutrientes sobre la prevención y tratam...

129I in volcanic fluids: Testing for the presence of marine sediments in the Central American volcanic arc

International Nuclear Information System (INIS)

Snyder, Glen; Fehn, Udo

2000-01-01

The long half-life and the geochemical behavior of the 129 I system suggest that this cosmogenic radioisotope can contribute significantly to the understanding of processes associated with subduction zones and volcanic arc systems. Because iodine is not incorporated into igneous rocks, the age-signal associated with 129 I permits the determination of the origin of volatiles within arc volcanic systems. We report here results of a study to test the application of 129 I in fluids collected from hotsprings, crater lakes, fumaroles and geothermal wells from the Central American volcanic arc. Both the Momotombo geothermal field in Nicaragua and the Miravalles geothermal field in Costa Rica show 129 I/I ratios consistent with magmatic contributions from subducted marine pelagic sediments (minimum iodine ages of 25-30 Ma). In addition, several wells provide iodine isotopic ratios indicative of an older end-member, presumably located in the shallow crust (minimum iodine age = 65 Ma)

Pucarilla-Cerro Tipillas volcanic complex: the oldest recognized caldera in the southeastern portion of central volcanic zone of Central Andes?

Energy Technology Data Exchange (ETDEWEB)

Guzman, Silvina; Petrinovic, Ivan [CONICET -IBIGEO. Museo de Cs. Naturales, Universidad de Salta, Mendoza 2 (4400), Salta (Argentina)], E-mail: guzmansilvina@gmail.com

2008-10-01

We recognize the most eastern and oldest collapse caldera structure in the southern portion of the Central Volcanic Zone of the Andes. A description of Middle-Upper Miocene successions related to explosive- effusive events is presented. The location of this centre close to Cerro Galn Caldera attests a recurrence in the volcanism between 12 and 2 Ma in this portion of the Altiplano - Puna Plateau.

Manejo endoscópico del vólvulo gástrico

OpenAIRE

Gómez, Martín Alonso; Ortiz, Camilo

2011-01-01

El vólvulo gástrico es una enfermedad muy rara que puede ser aguda o crónica y estar asociada a otras patologías. Es muy importante su rápida identificación porque de su tratamiento oportuno va a depender el pronóstico del paciente. Usualmente el manejo es quirúrgico con la gastropexia abierta o laparoscopia; sin embargo, puede intentarse un manejo endoscópico el cual es más rápido, sencillo y genera una menor morbilidad para los pacientes. Presentamos en este artículo dos casos de vólvulo gá...

Scaling properties of planetary calderas and terrestrial volcanic eruptions

Directory of Open Access Journals (Sweden)

L. Sanchez

2012-11-01

Full Text Available Volcanism plays an important role in transporting internal heat of planetary bodies to their surface. Therefore, volcanoes are a manifestation of the planet's past and present internal dynamics. Volcanic eruptions as well as caldera forming processes are the direct manifestation of complex interactions between the rising magma and the surrounding host rock in the crust of terrestrial planetary bodies. Attempts have been made to compare volcanic landforms throughout the solar system. Different stochastic models have been proposed to describe the temporal sequences of eruptions on individual or groups of volcanoes. However, comprehensive understanding of the physical mechanisms responsible for volcano formation and eruption and more specifically caldera formation remains elusive. In this work, we propose a scaling law to quantify the distribution of caldera sizes on Earth, Mars, Venus, and Io, as well as the distribution of calderas on Earth depending on their surrounding crustal properties. We also apply the same scaling analysis to the distribution of interevent times between eruptions for volcanoes that have the largest eruptive history as well as groups of volcanoes on Earth. We find that when rescaled with their respective sample averages, the distributions considered show a similar functional form. This result implies that similar processes are responsible for caldera formation throughout the solar system and for different crustal settings on Earth. This result emphasizes the importance of comparative planetology to understand planetary volcanism. Similarly, the processes responsible for volcanic eruptions are independent of the type of volcanism or geographical location.

Environmental and anthropogenic factors affecting the respiratory toxicity of volcanic ash in vitro

Science.gov (United States)

Tomašek, Ines; Horwell, Claire J.; Damby, David E.; Ayris, Paul M.; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J. D.

2016-04-01

Human exposure to inhalable volcanic ash particles following an eruption is a health concern, as respirable-sized particles can potentially contribute towards adverse respiratory health effects, such as the onset or exacerbation of respiratory and cardiovascular diseases. Although there is substantial information on the mineralogical properties of volcanic ash that may influence its biological reactivity, knowledge as to how external factors, such as air pollution, contribute to and augment the potential reactivity is limited. To determine the respiratory effects of volcanic particle interactions with anthropogenic pollution and volcanic gases we will experimentally assess: (i) physicochemical characteristics of volcanic ash relevant to respiratory toxicity; (ii) the effects of simultaneously inhaling anthropogenic pollution (i.e. diesel exhaust particles (DEP)) and volcanic ash (of different origins); (iii) alteration of volcanic ash toxicity following interaction with volcanic gases. In order to gain a first understanding of the biological impact of the respirable fraction of volcanic ash when inhaled with DEP in vitro, we used a sophisticated 3D triple cell co-culture model of the human alveolar epithelial tissue barrier. The multi-cellular system was exposed to DEP [0.02 mg/mL] and then exposed to either a single or repeated dose of well-characterised respirable volcanic ash (0.26 ± 0.09 or 0.89 ± 0.29 μg/cm2, respectively) from the Soufrière Hills volcano, Montserrat for a period of 24 hours using a pseudo-air liquid interface approach. Cultures were subsequently assessed for adverse biological endpoints including cytotoxicity, oxidative stress and (pro)-inflammatory responses. Results indicated that the combination of DEP and respirable volcanic ash at sub-lethal concentrations incited a significant release of pro-inflammatory markers that was greater than the response for either DEP or volcanic ash, independently. Further work is planned, to determine if

Cooling Rates of Lunar Volcanic Glass Beads

Science.gov (United States)

Hui, Hejiu; Hess, Kai-Uwe; Zhang, Youxue; Peslier, Anne; Lange, Rebecca; Dingwell, Donald; Neal, Clive

2016-01-01

It is widely accepted that the Apollo 15 green and Apollo 17 orange glass beads are of volcanic origin. The diffusion profiles of volatiles in these glass beads are believed to be due to degassing during eruption (Saal et al., 2008). The degree of degassing depends on the initial temperature and cooling rate. Therefore, the estimations of volatiles in parental magmas of lunar pyroclastic deposits depend on melt cooling rates. Furthermore, lunar glass beads may have cooled in volcanic environments on the moon. Therefore, the cooling rates may be used to assess the atmospheric condition in an early moon, when volcanic activities were common. The cooling rates of glasses can be inferred from direct heat capacity measurements on the glasses themselves (Wilding et al., 1995, 1996a,b). This method does not require knowledge of glass cooling environments and has been applied to calculate the cooling rates of natural silicate glasses formed in different terrestrial environments. We have carried out heat capacity measurements on hand-picked lunar glass beads using a Netzsch DSC 404C Pegasus differential scanning calorimeter at University of Munich. Our preliminary results suggest that the cooling rate of Apollo 17 orange glass beads may be 12 K/min, based on the correlation between temperature of the heat capacity curve peak in the glass transition range and glass cooling rate. The results imply that the parental magmas of lunar pyroclastic deposits may have contained more water initially than the early estimations (Saal et al., 2008), which used higher cooling rates, 60-180 K/min in the modeling. Furthermore, lunar volcanic glass beads could have been cooled in a hot gaseous medium released from volcanic eruptions, not during free flight. Therefore, our results may shed light on atmospheric condition in an early moon.

Sr isotopes at Copahue Volcanic Center, Neuquen, Argentina: Preliminary report

International Nuclear Information System (INIS)

Linares, E.; Ostera, H.A.; Cagnoni, M.C

2001-01-01

The Copahue Volcanic Center is located in the Cordillera Principal, at 38 L.S., in the Argentina- Chilean border. Detailed geological, geochronological and structural studies were carried out during the last decade (Pesce, 1989; Delpino y Bermudez, 1993; Linares et al., 1995, 1999; Folguera y Ramos, 2000; among others). We present Sr isotopes data on the main units of the Volcanic Center, coupled with a major element geochemistry, to constrain the evolution of the volcanic center (au)

Source mechanisms of volcanic tsunamis.

Science.gov (United States)

Paris, Raphaël

2015-10-28

Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness. © 2015 The Author(s).

The Earth System Science Pathfinder VOLCAM Volcanic Hazard Mission

Science.gov (United States)

Krueger, Arlin J.

1999-01-01

The VOLCAM mission is planned for research on volcanic eruptions and as a demonstration of a satellite system for measuring the location and density of volcanic eruption clouds for use in mitigating hazards to aircraft by the operational air traffic control systems. A requirement for 15 minute time resolution is met by flight as payloads of opportunity on geostationary satellites. Volcanic sulfur dioxide and ash are detected using techniques that have been developed from polar orbiting TOMS (UV) and AVHRR (IR) data. Seven band UV and three band IR filter wheel cameras are designed for continuous observation of the full disk of the earth with moderate (10 - 20 km) ground resolution. This resolution can be achieved with small, low cost instruments but is adequate for discrimination of ash and sulfur dioxide in the volcanic clouds from meteorological clouds and ozone. The false alarm rate is small through use of sulfur dioxide as a unique tracer of volcanic clouds. The UV band wavelengths are optimized to detect very small sulfur dioxide amounts that are present in pre-eruptive outgassing of volcanoes. The system is also capable of tracking dust and smoke clouds, and will be used to infer winds at tropopause level from the correlation of total ozone with potential vorticity.

K-Ar age of the Tertiary volcanic rocks in the Tohoku area, Japan

International Nuclear Information System (INIS)

Konda, Tadashi; Ueda, Yoshio.

1980-01-01

The absolute age of the Tertiary volcanic rocks in Tohoku area has been estimated by K-Ar method. The results are: (1) in case of the volcanic rocks of Monzen-Aikawa stage, 32.8 - 38.5 m.y.B.P., (2) in case of the volcanic rocks of Nozaki-Daijima stage, 22.0 - 25.1 m.y.B.P., (3) in case of the volcanic rocks of Nishikurosawa stage, 15.5 - 16.5 m.y.B.P., (4) in case of the volcanic rocks of Onnagawa stage, 12.6 - 14.8 m.y.B.P., (5) in case of the volcanic rocks of Funakawa stage, 9.6 - 11.3 m.y.B.P., and (6) in case of the volcanic rocks of Kitaura stage, 6.9 - 9.0 m.y.B.P. The samples used are such as biotite and whole rocks. The eruption periods in Tertiary volcanic activities presumed by K-Ar method are geologically significant. In the measurements made on the same system of samples under same conditions, there was difference in the K-Ar ages between the Monzen-Aikawa and the Nozaki-Daijima stages, and it was significantly noteworthy. It is indicated that the volcanic rock activities in the former stage had took place before those in the latter stage. In the Tohoku arc of northern Japan, the simultaneity in initial volcanic activities is not seen in the direction across the arc. (J.P.N.)

Progress in Near Real-Time Volcanic Cloud Observations Using Satellite UV Instruments

Science.gov (United States)

Krotkov, N. A.; Yang, K.; Vicente, G.; Hughes, E. J.; Carn, S. A.; Krueger, A. J.

2011-12-01

Volcanic clouds from explosive eruptions can wreak havoc in many parts of the world, as exemplified by the 2010 eruption at the Eyjafjöll volcano in Iceland, which caused widespread disruption to air traffic and resulted in economic impacts across the globe. A suite of satellite-based systems offer the most effective means to monitor active volcanoes and to track the movement of volcanic clouds globally, providing critical information for aviation hazard mitigation. Satellite UV sensors, as part of this suite, have a long history of making unique near-real time (NRT) measurements of sulfur dioxide (SO2) and ash (aerosol Index) in volcanic clouds to supplement operational volcanic ash monitoring. Recently a NASA application project has shown that the use of near real-time (NRT,i.e., not older than 3 h) Aura/OMI satellite data produces a marked improvement in volcanic cloud detection using SO2 combined with Aerosol Index (AI) as a marker for ash. An operational online NRT OMI AI and SO2 image and data product distribution system was developed in collaboration with the NOAA Office of Satellite Data Processing and Distribution. Automated volcanic eruption alarms, and the production of volcanic cloud subsets for multiple regions are provided through the NOAA website. The data provide valuable information in support of the U.S. Federal Aviation Administration goal of a safe and efficient National Air Space. In this presentation, we will highlight the advantages of UV techniques and describe the advances in volcanic SO2 plume height estimation and enhanced volcanic ash detection using hyper-spectral UV measurements, illustrated with Aura/OMI observations of recent eruptions. We will share our plan to provide near-real-time volcanic cloud monitoring service using the Ozone Mapping and Profiler Suite (OMPS) on the Joint Polar Satellite System (JPSS).

A light left in the dark: The practice and politics of pico-hydropower in the Lao PDR

NARCIS (Netherlands)

Smits, M.; Bush, S.R.

2010-01-01

The article describes the widespread use of an estimated 60,000 low-head pico-hydropower turbines and well-developed networks of supply and support in the Northern part of the Lao People's Democratic Republic (Lao PDR). This apparent widespread use is contrasted with the policy narratives of key

Qualidade das bulas de fitoterápicos no Brasil | Quality of the package inserts of phytomedicines in Brazil

Directory of Open Access Journals (Sweden)

Marcia Maria Barros dos Passos

2016-05-01

Full Text Available O objetivo deste trabalho foi avaliar se as bulas de medicamentos fitoterápicos industrializados estão de acordo com a legislação nacional vigente. Foram analisadas 41 bulas dos medicamentos fitoterápicos compostos por alcachofra, castanha da Índia, ginkgo e sene, adquiridas nos sites das empresas titulares dos registros. A análise foi feita quanto à presença de itens segundo a RDC nº 47 de 2009 e ao conteúdo de indicação de uso, posologia e reações adversas comparada às bulas padrão e à literatura científica. A análise quantitativa provou que as bulas têm cumprido o que é exigido pela legislação vigente. No entanto, quanto à análise qualitativa, todos os fitoterápicos analisados neste trabalho possuíam pelo menos uma bula com erro relacionado à posologia, indicações de uso e reações adversas. Houve uma melhora gradativa das bulas dos medicamentos fitoterápicos, porém mesmo com as bulas padrão ainda existem erros, que podem induzir o paciente ao uso incorreto do medicamento. -----------------------------------------------------------------------------------------------The objective of this study was to assess whether the package inserts of industrialized phytomedicines are in line with current Brazilian legislation or not. Forty-one package inserts of phytomedicines containing artichoke, horse chestnut, ginkgo and senna were accessed in the respective proprietary websites and then analyzed. The analysis aimed to verify the presence of items required by the normative RDC 47/2009 and the usage indication, dosage and side effects compared to standard package inserts and to the scientific literature. Quantitative analysis proved that the package inserts are in accordance with the current legislation. However, in qualitative analysis, all phytomedicines analyzed in this study had at least one error related to dosage, posology or adverse reactions. A gradual improvement of the package inserts of phytomedicines has

Volcanic sulfur degassing and the role of sulfides in controlling volcanic metal emissions

Science.gov (United States)

Edmonds, M.; Liu, E.

2017-12-01

Volcanoes emit prodigious quantities of sulfur and metals, their behaviour inextricably linked through pre-eruptive sulfide systematics and through degassing and speciation in the volcanic plume. Fundamental differences exist in the metal output of ocean island versus arc volcanoes, with volcanoes in Hawaii and Iceland outgassing large fluxes of gaseous and particulate chalcophiles; and arc volcanoes' plumes, in contrast, enriched in Zn, Cu, Tl and Pb. Metals and metalloids partition into a magmatic vapor phase from silicate melt at crustal pressures. Their abundance in magmatic vapor is influenced strongly by sulfide saturation and by the composition of the magmatic vapor phase, particularly with respect to chloride. These factors are highly dependent on tectonic setting. Metal outgassing is controlled by magma water content and redox: deep saturation in vapor and minimal sulfide in arc basalts yields metal-rich vapor; shallow degassing and resorption of sulfides feeds the metal content of volcanic gas in ocean islands. We present a detailed study of the sulfide systematics of the products of the 2014-2015 Holuhraun basaltic fissure eruption (Bárðarbunga volcanic system, Iceland) to illustrate the interplay between late water and sulfur outgassing; sulfide saturation and breakdown; and metal partitioning into a vapor phase. Sulfide globules, representing quenched droplets of an immiscible sulfide liquid, are preserved within erupted tephra. Sulfide globules in rapidly quenched tephra are preserved within both matrix glass and as inclusions in crystals. The stereologically-corrected 3D size distribution of sulfide globules ranges from importance in supplying sulfur and metals to the atmosphere during eruption.

Role of Atmospheric Chemistry in the Climate Impacts of Stratospheric Volcanic Injections

Science.gov (United States)

Legrande, Allegra N.; Tsigaridis, Kostas; Bauer, Susanne E.

2016-01-01

The climate impact of a volcanic eruption is known to be dependent on the size, location and timing of the eruption. However, the chemistry and composition of the volcanic plume also control its impact on climate. It is not just sulfur dioxide gas, but also the coincident emissions of water, halogens and ash that influence the radiative and climate forcing of an eruption. Improvements in the capability of models to capture aerosol microphysics, and the inclusion of chemistry and aerosol microphysics modules in Earth system models, allow us to evaluate the interaction of composition and chemistry within volcanic plumes in a new way. These modeling efforts also illustrate the role of water vapor in controlling the chemical evolution, and hence climate impacts, of the plume. A growing realization of the importance of the chemical composition of volcanic plumes is leading to a more sophisticated and realistic representation of volcanic forcing in climate simulations, which in turn aids in reconciling simulations and proxy reconstructions of the climate impacts of past volcanic eruptions. More sophisticated simulations are expected to help, eventually, with predictions of the impact on the Earth system of any future large volcanic eruptions.

Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards

Science.gov (United States)

Ham, H. J.; Lee, S.; Choi, S. H.; Yun, W. S.

2015-12-01

Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards Hee Jung Ham1, Seung-Hun Choi1, Woo-Seok Yun1, Sungsu Lee2 1Department of Architectural Engineering, Kangwon National University, Korea 2Division of Civil Engineering, Chungbuk National University, Korea ABSTRACT In this study, fragility functions are developed to estimate expected volcanic ash damages of the agricultural sector in Korea. The fragility functions are derived from two approaches: 1) empirical approach based on field observations of impacts to agriculture from the 2006 eruption of Merapi volcano in Indonesia and 2) the FOSM (first-order second-moment) analytical approach based on distribution and thickness of volcanic ash observed from the 1980 eruption of Mt. Saint Helens and agricultural facility specifications in Korea. Fragility function to each agricultural commodity class is presented by a cumulative distribution function of the generalized extreme value distribution. Different functions are developed to estimate production losses from outdoor and greenhouse farming. Seasonal climate influences vulnerability of each agricultural crop and is found to be a crucial component in determining fragility of agricultural commodities to an ash fall. In the study, the seasonality coefficient is established as a multiplier of fragility function to consider the seasonal vulnerability. Yields of the different agricultural commodities are obtained from Korean Statistical Information Service to create a baseline for future agricultural volcanic loss estimation. Numerically simulated examples of scenario ash fall events at Mt. Baekdu volcano are utilized to illustrate the application of the developed fragility functions. Acknowledgements This research was supported by a grant 'Development of Advanced Volcanic Disaster Response System considering Potential Volcanic Risk around Korea' [MPSS-NH-2015-81] from the Natural Hazard Mitigation Research Group, Ministry of Public Safety and Security of

Toward Assessing the Causes of Volcanic Diversity in the Cascades Arc

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Till, C. B.; Kent, A. J.; Abers, G. A.; Pitcher, B.; Janiszewski, H. A.; Schmandt, B.

2017-12-01

A fundamental unanswered question in subduction system science is the cause of the observed diversity in volcanic arc style at an arc-segment to whole-arc scale. Specifically, we have yet to distinguish the predominant mantle and crustal processes responsible for the diversity of arc volcanic phenomenon, including the presence of central volcanoes vs. dispersed volcanism; episodicity in volcanic fluxes in time and space; variations in magma chemistry; and differences in the extent of magmatic focusing. Here we present a thought experiment using currently available data to estimate the relative role of crustal magmatic processes in producing the observed variations in Cascades arc volcanism. A compilation of available major element compositions of Quaternary arc volcanism and estimates of eruptive volumes are used to examine variations in the composition of arc magmas along strike. We then calculate the Quaternary volcanic heat flux into the crust, assuming steady state, required to produce the observed distribution of compositions via crystallization of mantle-derived primitive magmas vs. crustal melting using experiment constraints on possible liquid lines of descent and crustal melting scenarios. For pure crystallization, heat input into the crust scales with silica content, with dacitic to rhyolite compositions producing significantly greater latent heat relative to basalts to andesites. In contrast, the heat required to melt lower crustal amphibolite decreases with increasing silica and is likely provided by the latent heat of crystallization. Thus we develop maximum and minimum estimates for heat added to the crust at a given SiO2 range. When volumes are considered, we find that the average Quaternary volcanic heat flux at latitudes south of South Sister to be more than twice that to the north. Distributed mafic volcanism produces only a quarter to half the heat flux calculated for the main edifices at a given latitude because of their lesser eruptive volumes

Study on the Effect of Straw Fiber on the Performance of Volcanic Slag Concrete

Science.gov (United States)

Xiao, Li-guang; Liu, Xi-xu

2018-03-01

In this paper, the effects of straw fiber on the working performance, mechanical properties and frost resistance of volcanic slag lightweight aggregate concrete were studied. The experimental results show that the straw fiber is subjected to surface carbonization treatment and mixed into the volcanic slag light aggregate concrete. The flexural strength and fracture pressure ratio of volcanic slag lightweight aggregate concrete are improved obviously Improved volcanic slag lightweight aggregate concrete brittleness improves toughness. Carbonized straw fiber greatly improves the frost resistance of volcanic slag lightweight aggregate concrete. So that the volcanic slag light aggregate concrete freeze-thaw cycle can reach 300 times.

A Rapid Label-Free Fluorescent Aptasensor PicoGreen-Based Strategy for Aflatoxin B₁ Detection in Traditional Chinese Medicines.

Science.gov (United States)

Zhang, Cheng; Dou, Xiaowen; Zhang, Lei; Sun, Meifeng; Zhao, Ming; OuYang, Zhen; Kong, Dandan; Antonio, F Logrieco; Yang, Meihua

2018-02-28

Aflatoxin B₁ (AFB₁) is a very hazardous carcinogen, readily contaminating foodstuffs and traditional Chinese medicines (TCMs) that has inspired increasing health concerns due to dietary exposure. Colloidal nanocrystals have been proposed as optical labels for aptasensor assembly, but these typically require tedious multistep conjugation and suffer from unsatisfactory robustness when used for complex matrices. In the present study, we report a rapid and sensitive method for screening for trace AFB₁ levels in TCMs using a label-free fluorescent aptasensor PicoGreen dye-based strategy. Using PicoGreen to selectively measure complementary double-stranded DNA, fluorescence enhancement due to dsDNA is 'turned off' in the presence of AFB₁ due binding of aptamer target over complementary sequence. Self-assembly of a label-free fluorescent aptasensor based on AFB₁ aptamer and PicoGreen dye was performed. Due to competition between the complementary sequence and AFB₁ target, this rapid method was capable of highly sensitive and selective screening for AFB₁ in five types of TCMs. This proposed approach had a limit of detection as low as 0.1 μg·L -1 and good linearity with a range of 0.1-10 μg·L -1 (0.1-10 ppb). Among the 20 samples tested, 6 batches were found to be contaminated with AFB₁ using this method, which was confirmed using sophisticated liquid chromatography-electrospray ionization-tandem mass spectrometry/mass spectrometry analysis. The results of this study indicate the developed method has the potential to be a simple, quick, and sensitive tool for detecting AFB₁ in TCMs.

Volcanic mercury in Pinus canariensis

Science.gov (United States)

Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis

2013-08-01

Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg-1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg-1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg-1) and bark (6.0 μg kg-1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.

Source mechanism of volcanic tremor

Energy Technology Data Exchange (ETDEWEB)

Ferrick, M.G.; Qamar, A.; St. Lawrence, W.F.

1982-10-10

Low-frequency (<10 Hz) volcanic earthquakes originate at a wide range of depths and occur before, during, and after magmatic eruptions. The characteristics of these earthquakes suggest that they are not typical tectonic events. Physically analogous processes occur in hydraulic fracturing of rock formations, low-frequency icequakes in temperate glaciers, and autoresonance in hydroelectric power stations. We propose that unsteady fluid flow in volcanic conduits is the common source mechanism of low-frequency volcanic earthquakes (tremor). The fluid dynamic source mechanism explains low-frequency earthquakes of arbitrary duration, magnitude, and depth of origin, as unsteady flow is independent of physical properties of the fluid and conduit. Fluid transients occur in both low-viscosity gases and high-viscosity liquids. A fluid transient analysis can be formulated as generally as is warranted by knowledge of the composition and physical properties of the fluid, material properties, geometry and roughness of the conduit, and boundary conditions. To demonstrate the analytical potential of the fluid dynamic theory, we consider a single-phase fluid, a melt of Mount Hood andesite at 1250/sup 0/C, in which significant pressure and velocity variations occur only in the longitudinal direction. Further simplification of the conservation of mass and momentum equations presents an eigenvalue problem that is solved to determine the natural frequencies and associated damping of flow and pressure oscillations.

Volcanic mercury in Pinus canariensis.

Science.gov (United States)

Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis

2013-08-01

Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg(-1)) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg(-1)). Thus, mercury emissions originating from the eruption remained only as a mark-in pyroclastic wounds-and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg(-1)) and bark (6.0 μg kg(-1)) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.

IMP Supersite vs Pico de Tres Padres: The first few hours of mixing and oxidation during the MCMA-2006/MILAGRO Campaign

Science.gov (United States)

Herndon, S.; Onasch, T.; Wood, E.; Knighton, B.; Zavala, M.; Mazzoleni, C.; Thornhill, D.; Marr, L.; Kolb, C.; Molina, L. T.

2007-05-01

The Aerodyne Research, Inc. (ARI) mobile laboratory was deployed in the Mexico City Metropolitan Area (MCMA) for the full month of March 2006 to support the MCMA-2006/MAX-Mex/MILAGRO research project activities, in collaboration with other MCMA-2006 research groups (see information on MCMA-2006/MILAGRO posted at http:www.mce2.org). The ratios of various volatile organic compounds (VOCs) to combustion tracer species such as CO and CO2 are compared at one of the supersites (T0) and Pico de Tres Padres. T0 (located at the Mexican Petroleum Institute, IMP) is heavily influenced by various emission sources in the local area, predominantly roadway traffic. Pico de Tres Padres is an isolated, privately owned mountain located within the Mexico City Metropolitan Area (MCMA). It rises 1000 m above the MCMA basin floor and is located about halfway between T0 and T1. The airmasses analyzed at Pico de Tres Padres seem to be mixed urban emissions absent of high frequency spikes of CO, NO or CO2. Relationships between VOCs, and combustion tracers will be used to gain a crude understanding of the initial photochemical processing of the urban emissions. How the initial photochemical processing of Mexico City's air may relate to secondary aerosol production is also explored.

Local to global: a collaborative approach to volcanic risk assessment

Science.gov (United States)

Calder, Eliza; Loughlin, Sue; Barsotti, Sara; Bonadonna, Costanza; Jenkins, Susanna

2017-04-01

Volcanic risk assessments at all scales present challenges related to the multitude of volcanic hazards, data gaps (hazards and vulnerability in particular), model representation and resources. Volcanic hazards include lahars, pyroclastic density currents, lava flows, tephra fall, ballistics, gas dispersal and also earthquakes, debris avalanches, tsunamis and more ... they can occur in different combinations and interact in different ways throughout the unrest, eruption and post-eruption period. Volcanoes and volcanic hazards also interact with other natural hazards (e.g. intense rainfall). Currently many hazards assessments consider the hazards from a single volcano but at national to regional scales the potential impacts of multiple volcanoes over time become important. The hazards that have the greatest tendency to affect large areas up to global scale are those transported in the atmosphere: volcanic particles and gases. Volcanic ash dispersal has the greatest potential to directly or indirectly affect the largest number of people worldwide, it is currently the only volcanic hazard for which a global assessment exists. The quantitative framework used (primarily at a regional scale) considers the hazard at a given location from any volcano. Flow hazards such as lahars and floods can have devastating impacts tens of kilometres from a source volcano and lahars can be devastating decades after an eruption has ended. Quantitative assessment of impacts is increasingly undertaken after eruptions to identify thresholds for damage and reduced functionality. Some hazards such as lava flows could be considered binary (totally destructive) but others (e.g. ash fall) have varying degrees of impact. Such assessments are needed to enhance available impact and vulnerability data. Currently, most studies focus on physical vulnerability but there is a growing emphasis on social vulnerability showing that it is highly variable and dynamic with pre-eruption socio

GIS database and discussion for the distribution, composition, and age of Cenozoic volcanic rocks of the Pacific Northwest Volcanic Aquifer System study area

Science.gov (United States)

Sherrod, David R.; Keith, Mackenzie K.

2018-03-30

A substantial part of the U.S. Pacific Northwest is underlain by Cenozoic volcanic and continental sedimentary rocks and, where widespread, these strata form important aquifers. The legacy geologic mapping presented with this report contains new thematic categorization added to state digital compilations published by the U.S. Geological Survey for Oregon, California, Idaho, Nevada, Utah, and Washington (Ludington and others, 2005). Our additional coding is designed to allow rapid characterization, mainly for hydrogeologic purposes, of similar rocks and deposits within a boundary expanded slightly beyond that of the Pacific Northwest Volcanic Aquifer System study area. To be useful for hydrogeologic analysis and to be more statistically manageable, statewide compilations from Ludington and others (2005) were mosaicked into a regional map and then reinterpreted into four main categories on the basis of (1) age, (2) composition, (3) hydrogeologic grouping, and (4) lithologic pattern. The coding scheme emphasizes Cenozoic volcanic or volcanic-related rocks and deposits, and of primary interest are the codings for composition and age.

Volcanology: Volcanic bipolar disorder explained

Science.gov (United States)

Jellinek, Mark

2014-02-01

Eruptions come in a range of magnitudes. Numerical simulations and laboratory experiments show that rare, giant super-eruptions and smaller, more frequent events reflect a transition in the essential driving forces for volcanism.

[Effects of volcanic eruptions on environment and health].

Science.gov (United States)

Zuskin, Eugenija; Mustajbegović, Jadranka; Doko Jelinić, Jagoda; Pucarin-Cvetković, Jasna; Milosević, Milan

2007-12-01

Volcanoes pose a threat to almost half a billion people; today there are approximately 500 active volcanoes on Earth, and every year there are 10 to 40 volcanic eruptions. Volcanic eruptions produce hazardous effects for the environment, climate, and the health of the exposed persons, and are associated with the deterioration of social and economic conditions. Along with magma and steam (H2O), the following gases surface in the environment: carbon dioxide (CO2) and sulphur dioxide (SO2), carbon monoxide (CO), hydrogen sulphide (H2S), carbon sulphide (CS), carbon disulfide (CS2), hydrogen chloride (HCl), hydrogen (H2), methane (CH4), hydrogen fluoride (HF), hydrogen bromide (HBr) and various organic compounds, as well as heavy metals (mercury, lead, gold).Their unfavourable effects depend on the distance from a volcano, on magma viscosity, and on gas concentrations. The hazards closer to the volcano include pyroclastic flows, flows of mud, gases and steam, earthquakes, blasts of air, and tsunamis. Among the hazards in distant areas are the effects of toxic volcanic ashes and problems of the respiratory system, eyes and skin, as well as psychological effects, injuries, transport and communication problems, waste disposal and water supplies issues, collapse of buildings and power outage. Further effects are the deterioration of water quality, fewer periods of rain, crop damages, and the destruction of vegetation. During volcanic eruptions and their immediate aftermath, increased respiratory system morbidity has been observed as well as mortality among those affected by volcanic eruptions. Unfavourable health effects could partly be prevented by timely application of safety measures.

Scientific Drilling in a Central Italian Volcanic District

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Paola Montone

2007-09-01

Full Text Available The Colli Albani Volcanic District, located 15 km SE of Rome (Fig. 1, is part of the Roman Magmatic Province, a belt of potassic to ultra-potassic volcanic districts that developed along the Tyrrhenian Sea margin since Middle Pleistocene time (Conticelli and Peccerillo, 1992; Marra et al., 2004; Giordano et al., 2006 and references therein. Eruption centers are aligned along NW-SE oriented majorextensional structures guiding the dislocation of Meso-Cenozoic siliceous-carbonate sedimentary successions at the rear of the Apennine belt. Volcanic districts developed in structural sectors with most favorable conditions for magma uprise. In particular, the Colli Albani volcanism is located in a N-S shear zone where it intersects the extensional NW- and NE-trending fault systems. In the last decade, geochronological measurements allowed for reconstructions of the eruptive history and led to the classification as "dormant" volcano. The volcanic history may be roughly subdivided into three main phases marked by different eruptive mechanisms andmagma volumes. The early Tuscolano-Artemisio Phase (ca. 561–351 ky, the most explosive and voluminous one, is characterized by five large pyroclastic flow-forming eruptions. After a ~40-ky-long dormancy, a lesser energetic phase of activity took place (Faete Phase; ca. 308–250 ky, which started with peripheral effusive eruptions coupled with subordinate hydromagmatic activity. A new ~50-ky-long dormancypreceded the start of the late hydromagmatic phase (ca. 200–36 ky, which was dominated by pyroclastic-surge eruptions, with formation of several monogenetic or multiple maars and/or tuff rings.

Grafito isotrópico obtenido a partir de coque para aplicaciones en automoción

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Oñoro, J.

2004-04-01

Full Text Available The graphite is an allotropic form of the element carbon consisting of layers of hexagonally arranged carbon atoms in a planar condensed ring system. Coke particles used for conventional synthetic graphite products are long and narrow. These particles produce a preferred structural orientation in the product after the conventional uniaxial pressing or extrusion with high anisotropy. With a properly election of raw materials and process is possible reduce the anisotropy to obtain isotropic graphite. Repsol-YPF has produced a binderless polyaromatic mesophase from petroleum pitch, which has shown to be very appropriated as raw material for production of high strength isotropic graphite with high performance and low cost. This graphite have offered thermal, mechanical, chemical and wear properties higher than conventional graphite. The isotropic graphite obtained is suitable for making pistons, valves, turbojoints and other automotives components. The pistons design with this isotropic graphite has been developed for an automotive petrol engine. Piston prototypes were manufactured and tested in engines at full power and at full torque. This paper analysed the physical, mechanical and fracture properties of the isotropic graphite obtained.

El grafito es una forma alotrópica del carbono, consistente en capas de átomos de carbono cristalizados en anillos hexagonales planos. Las partículas de coque utilizadas para sintetizar el grafito convencional son largas y estrechas, lo que da lugar a una estructura orientada de alta anisotropía tras un proceso de compactación o extrusión. Con una adecuada selección de materias primas y procesos de conformado es posible reducir dicha anisotropía, hasta eliminarla en la obtención del grafito isotrópico. La empresa Repsol-YPF, S.A., ha desarrollado un proceso para la fabricación de una mesofase poliaromática extraída por carbonización de residuos del refino del petróleo, a partir de la cual se

Evidences for a volcanic province in the Central Indian Basin

Digital Repository Service at National Institute of Oceanography (India)

Iyer, S.D.; Sudhakar, M.

Based on various lines of evidence such as the widespread occurrence of basalts, pumice, volcanic glass shards and their transformational products (zeolites, palagonites, and smectite-rich sediments), we suggest the presence of a volcanic province...

Posicionamento ectópico de eletrodo de marcapasso Posicionamiento ectópico de electrodo de marcapaso Ectopic positioning of pacemaker electrode

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Gildo Mota

2010-05-01

Full Text Available Apresentamos o caso de um paciente portador da forma cardíaca da doença de Chagas com disfunção ventricular esquerda e bloqueio atrioventricular de 2º grau Mobitz II, associados a vários episódios de síncope. Foi submetido a implante de marcapasso artificial definitivo dupla câmara. Após um ano do implante foi diagnosticado deslocamento de eletrodo atrial, sendo submetido a reimplante de eletrodo atrial. Após dois anos do primeiro procedimento cirúrgico, apresentava dispneia aos grandes esforços. Durante a avaliação, foi solicitado ecocardiograma, que detectou a presença de corpo estranho de características metálicas em câmaras cardíacas esquerdas, consistente com eletrodo de marcapasso ectópico.Referimos el caso de un paciente portador de la forma cardíaca de la enfermedad de Chagas con disfunción ventricular izquierda y bloqueo atrioventricular de 2° grado Mobitz II, asociados a varios episodios de síncope. Fue sometido a implante de marcapaso artificial definitivo doble cámara. Tras un año del implante se diagnosticó desplazamiento de electrodo atrial, con la sumisión del paciente a reimplante de electrodo atrial. Tras dos años del primer procedimiento quirúrgico, presentaba disnea a los grandes esfuerzos. Durante la evaluación, se solicitó ecocardiograma, que detectó presencia de cuerpo extraño de características metálicas en cámaras cardíacas izquierdas, de acuerdo con electrodo de marcapaso ectópico.The present case reports on a patient presenting the cardiac form of Chagas disease, with left ventricular dysfunction and second-degree atrioventricular block Mobitz type II, associated with several syncope episodes. The patient underwent a double-chamber definitive artificial pacemaker implant. One year after the implant, the displacement of the atrial electrode was diagnosed and the patient was submitted to re-implantation of the atrial electrode. Two years after the first surgical procedure, the

Considerations on comprehensive risk assessment and mitigation planning of volcanic ash-fall

International Nuclear Information System (INIS)

Toshida, Kiyoshi

2010-01-01

Volcanic ash-fall is inevitable hazard throughout Japan, and causes wide range of effects due to its physical and chemical properties. Nuclear power plants in Japan face the necessity to assess the risk from volcanic ash-fall. Risk assessment of the volcanic ash-fall should include engineering solution and mitigation planning as well as the ash-fall hazard. This report points out the characteristics for reducing the various effects of volcanic ash-fall as follows. Large-scale eruptions produce prominent volcanic ash-falls that can approach power plants at a great distance. Aftermath hazards of ash-fall events, such as remobilization of fine ash particles and generation of lahars, require further assessments. The kind and extent of damages becomes greater whenever ash is wet. Wet ash requires separate assessments in contrast to dry ash. The mitigation and recovery measures at power plants involve quick cleanup operations of volcanic ash. Those operations should be prepared through comprehensive risk assessment, and by cooperation with authorities, during pre-eruption repose period. The comprehensive assessment for volcanic ash-fall hazards, however, has yet to be conducted. Development of risk communication method may result in increased implementation mitigation planning. Numerical analysis of the ash-fall hazards provides quantitative data on particle motions that can be used in the risk assessment. In order to implement the quantitative assessment method, the verification on the effect of ambient air condition to the altitude of volcanic ash cloud is necessary. We need to develop a three-dimensional model of volcanic ash cloud, and calculate motions of ash clouds under multiple conditions of ambient air. (author)

Pico e’ lapa: Filosofía de una ironía trágica. Una relectura aristotélica

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Andrés Solano Fallas

2016-10-01

Full Text Available En este artículo se realiza una relectura aristotélica sobre cuatro temas que, enmarcados en el concepto de ironía, aparecen en la novela costarricense Los Hijos del Diablo. Pico e’ Lapa, el último de Minor Herrera-Valenciano. Se define qué es ironía de acuerdo con Aristóteles y posteriormente se analizan los temas seleccionados como ejemplos de esta figura, estos son: la decisión de un padre, perder el miedo, sobre las amistades peligrosas y la ley del silencio (justicia. Cada uno responde a asuntos propiamente de la Ética a Nicómaco (la decisión, el miedo, la amistad, la justicia; en lugar de tratarlos individualmente, se les engloba como ejemplos irónicos de la vida de Pico e’ Lapa.

The Western Arabian intracontinental volcanic fields as a potential UNESCO World Heritage site

Science.gov (United States)

Németh, Károly; Moufti, Mohammed R.

2017-04-01

UNESCO promotes conservation of the geological and geomoprhological heritage through promotion of protection of these sites and development of educational programs under the umbrella of geoparks among the most globally significant ones labelled as UNESCO Global Geoparks. UNESCO also maintains a call to list those natural sites that provide universal outstanding values to demonstrate geological features or their relevance to our understanding the evolution of Earth. Volcanoes currently got a surge in nomination to be UNESCO World Heritage sites. Volcanic fields in the contrary fell in a grey area of nominations as they represents the most common manifestation of volcanism on Earth hence they are difficult to view as having outstanding universal values. A nearly 2500-km long 300-km wide region of dispersed volcanoes located in the Western Arabian Penninsula mostly in the Kingdom of Saudi Arabia form a near-continuous location that carries universal outstanding value as one of the most representative manifestation of dispersed intracontinental volcanism on Earth to be nominated as an UNESCO World Heritage site. The volcanic fields formed in the last 20 Ma along the Red Sea as group of simple basaltic to more mature and long-lived basalt to trachyte-to-rhyolite volcanic fields each carries high geoheritage values. While these volcanic fields are dominated by scoria and spatter cones and transitional lava fields, there are phreatomagmatic volcanoes among them such as maars and tuff rings. Phreatomagmatism is more evident in association with small volcanic edifices that were fed by primitive magmas, while phreatomagmatic influences during the course of a larger volume eruption are also known in association with the silicic eruptive centres in the harrats of Rahat, Kishb and Khaybar. Three of the volcanic fields are clearly bimodal and host small-volume relatively short-lived lava domes and associated block-and-ash fans providing a unique volcanic landscape commonly not

Size limits for rounding of volcanic ash particles heated by lightning

Science.gov (United States)

Wadsworth, Fabian B.; Vasseur, Jérémie; Llewellin, Edward W.; Genareau, Kimberly; Cimarelli, Corrado; Dingwell, Donald B.

2017-03-01

Volcanic ash particles can be remelted by the high temperatures induced in volcanic lightning discharges. The molten particles can round under surface tension then quench to produce glass spheres. Melting and rounding timescales for volcanic materials are strongly dependent on heating duration and peak temperature and are shorter for small particles than for large particles. Therefore, the size distribution of glass spheres recovered from ash deposits potentially record the short duration, high-temperature conditions of volcanic lightning discharges, which are hard to measure directly. We use a 1-D numerical solution to the heat equation to determine the timescales of heating and cooling of volcanic particles during and after rapid heating and compare these with the capillary timescale for rounding an angular particle. We define dimensionless parameters—capillary, Fourier, Stark, Biot, and Peclet numbers—to characterize the competition between heat transfer within the particle, heat transfer at the particle rim, and capillary motion, for particles of different sizes. We apply this framework to the lightning case and constrain a maximum size for ash particles susceptible to surface tension-driven rounding, as a function of lightning temperature and duration, and ash properties. The size limit agrees well with maximum sizes of glass spheres found in volcanic ash that has been subjected to lightning or experimental discharges, demonstrating that the approach that we develop can be used to obtain a first-order estimate of lightning conditions in volcanic plumes.

Geochemical study of two obsidian production centers in the Prehistory of Tenerife: El Tabonal de los Guanches (Icod de los Vinos and el Tabonal Negro (Las Cañadas

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Hernández Gómez, Cristo M.

2008-12-01

Full Text Available The obsidian production is one of the work processes that allow a good characterization of the Guanches, first inhabitants of Tenerife (Canary Islands. On this occasion, addresses the geochemical study of the volcanic flows where the main obsidian sources of the Aboriginal of Tenerife are located: The Tabonal de Los Guanches (Icod de Los Vinos and the Tabonal Negro, Mña. Blanca (Las Cañadas del Teide characterized as Production Centres. The aim is to establish the compositional differences between the two in order to trace the distribution of their lithic productions in the island territory and recognize the pattern of supply that was put into practice.

La producción obsidiánica es uno de los procesos de trabajo que mejor permite la caracterización social de los guanches, primeros habitantes de Tenerife (Canarias. En esta ocasión se aborda el estudio geoquímico de las coladas en las que se ubican sus principales fuentes de aprovisionamiento de obsidiana: El Tabonal de Los Guanches (Icod de los Vinos y El Tabonal Negro en Mña. Blanca (Las Cañadas del Teide, consideradas desde el punto de vista arqueológico como Centros de Producción. El objetivo es establecer las diferencias composicionales entre ambas para poder rastrear la distribución de sus respectivas producciones líticas en el territorio insular y reconocer el modelo de suministro que se puso en práctica.

Volcanic risk perception in the Campi Flegrei area

Science.gov (United States)

Ricci, T.; Barberi, F.; Davis, M. S.; Isaia, R.; Nave, R.

2013-03-01

The Campi Flegrei which includes part of the city of Naples, is an active volcanic system; its last eruption occurred in 1538 AD. More recently two significant crises occurred between 1969 and 72 and 1982-84 and were accompanied by ground movements (bradyseism) and seismic activity, forcing people of the town of Pozzuoli to be evacuated. Since 1984 development of a volcanic emergency plan has been underway. In 2000 Civil Protection published a risk map which defined the Red Zone, an area highly at risk from pyroclastic flows, which would need to be evacuated before an eruption. The first study to evaluate the volcanic risk perceptions of the people living within the Campi Flegrei area was completed in spring 2006, resulting in the largest sample ever studied on this topic except for one on Vesuvio area residents by Barberi et al. (2008). A 46 item questionnaire was distributed to 2000 of the approximately 300,000 residents of the Campi Flegrei Red Zone, which includes three towns and four neighborhoods within the city of Naples. A total of 1161 questionnaires were returned, for an overall response rate of 58%. Surveys were distributed to junior high and high school students, as well as to adult members of the general population. Results indicated that unlike issues such as crime, traffic, trash, and unemployment, volcanic hazards are not spontaneously mentioned as a major problem facing their community. However, when asked specific questions about volcanic risks, respondents believe that an eruption is likely and could have serious consequences for themselves and their communities and they are quite worried about the threat. Considering the events of 1969-72 and 1982-84, it was not surprising that respondents indicated earthquakes and ground deformations as more serious threats than eruptive phenomena. Of significant importance is that only 17% of the sample knows about the existence of the Emergency Plan, announced in 2001, and 65% said that they have not received

Winter warming from large volcanic eruptions

Science.gov (United States)

Robock, Alan; Mao, Jianping

1992-01-01

An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95-percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

Can rain cause volcanic eruptions?

Science.gov (United States)

Mastin, Larry G.

1993-01-01

Volcanic eruptions are renowned for their violence and destructive power. This power comes ultimately from the heat and pressure of molten rock and its contained gases. Therefore we rarely consider the possibility that meteoric phenomena, like rainfall, could promote or inhibit their occurrence. Yet from time to time observers have suggested that weather may affect volcanic activity. In the late 1800's, for example, one of the first geologists to visit the island of Hawaii, J.D. Dana, speculated that rainfall influenced the occurrence of eruptions there. In the early 1900's, volcanologists suggested that some eruptions from Mount Lassen, Calif., were caused by the infiltration of snowmelt into the volcano's hot summit. Most such associations have not been provable because of lack of information; others have been dismissed after careful evaluation of the evidence.

Geochemical constraints on the relationship between the Miocene-Pliocene volcanism and tectonics in the Palaoco and Fortunoso volcanic fields, Mendoza Region, Argentina

DEFF Research Database (Denmark)

Dyhr, Charlotte Thorup; Holm, Paul Martin; Llambias, Eduardo J.

2013-01-01

New 40Ar/39Ar analyses constrain the formation of the volcanic succession of Sierra de Palaoco in the present back-arc of the Andean Southern Volcanic Zone (SVZ), near 36°S, to the Late Miocene and assigns them to the Huincán II Formation. The composition of major and trace elements, Sr, Nd and P...

Forecasters Handbook for Central America and Adjacent Waters

Science.gov (United States)

1989-09-01

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Impact of major volcanic eruptions on stratospheric water vapour

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M. Löffler

2016-05-01

Full Text Available Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry–climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg – Modular Earth Submodel System (ECHAM/MESSy Atmospheric Chemistry (EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño–Southern Oscillation (ENSO are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

Communicating Uncertainty in Volcanic Ash Forecasts: Decision-Making and Information Preferences

Science.gov (United States)

Mulder, Kelsey; Black, Alison; Charlton-Perez, Andrew; McCloy, Rachel; Lickiss, Matthew

2016-04-01

The Robust Assessment and Communication of Environmental Risk (RACER) consortium, an interdisciplinary research team focusing on communication of uncertainty with respect to natural hazards, hosted a Volcanic Ash Workshop to discuss issues related to volcanic ash forecasting, especially forecast uncertainty. Part of the workshop was a decision game in which participants including forecasters, academics, and members of the Aviation Industry were given hypothetical volcanic ash concentration forecasts and asked whether they would approve a given flight path. The uncertainty information was presented in different formats including hazard maps, line graphs, and percent probabilities. Results from the decision game will be presented with a focus on information preferences, understanding of the forecasts, and whether different formats of the same volcanic ash forecast resulted in different flight decisions. Implications of this research will help the design and presentation of volcanic ash plume decision tools and can also help advise design of other natural hazard information.

Unexpected HIMU-type late-stage volcanism on the Walvis Ridge

Science.gov (United States)

Homrighausen, S.; Hoernle, K.; Geldmacher, J.; Wartho, J.-A.; Hauff, F.; Portnyagin, M.; Werner, R.; van den Bogaard, P.; Garbe-Schönberg, D.

2018-06-01

Volcanic activity at many oceanic volcanoes, ridges and plateaus often reawakens after hiatuses of up to several million years. Compared to the earlier magmatic phases, this late-stage (rejuvenated/post-erosional) volcanism is commonly characterized by a distinct geochemical composition. Late-stage volcanism raises two hitherto unanswered questions: Why does volcanism restart after an extended hiatus and what is the origin of this volcanism? Here we present the first 40Ar/39Ar age and comprehensive trace element and Sr-Nd-Pb-Hf isotopic data from seamounts located on and adjacent to the Walvis Ridge in the South Atlantic ocean basin. The Walvis Ridge is the oldest submarine part of the Tristan-Gough hotspot track and is famous as the original type locality for the enriched mantle one (EM I) end member. Consistent with the bathymetric data, the age data indicates that most of these seamounts are 20-40 Myr younger than the underlying or nearby Walvis Ridge basement. The trace element and isotope data reveal a distinct compositional range from the EM I-type basement. The composition of the seamounts extend from the St. Helena HIMU (high time-integrated 238U/204Pb mantle with radiogenic Pb isotope ratios) end member to an enriched (E) Mid-Ocean-Ridge Basalt (MORB) type composition, reflecting a two-component mixing trend on all isotope diagrams. The EMORB end member could have been generated through mixing of Walvis Ridge EM I with normal (N) MORB source mantle, reflecting interaction of Tristan-Gough (EM I-type) plume melts with the upper mantle. The long volcanic quiescence and the HIMU-like geochemical signature of the seamounts are unusual for classical hotspot related late-stage volcanism, indicating that these seamounts are not related to the Tristan-Gough hotspot volcanism. Two volcanic arrays in southwestern Africa (Gibeon-Dicker Willem and Western Cape province) display similar ages to the late-stage Walvis seamounts and also have HIMU-like compositions

Division of volcanic activity cycles in the late mesozoic in South Jiangxi and North Guangdong

International Nuclear Information System (INIS)

Li Qinglong; Wu Jianhua

1999-01-01

Based on stratigraphical unconformity, rock association, fossil assemblage, isotope age and tectonic features, the volcanic activity in late Mesozoic in south Jiangxi and north Guandong can be divided into four cycles: Yutian volcanic activity cycle, Lianhuazhai volcanic activity cycle. Banshi volcanic activity cycle and Nanxiong volcanic activity cycle. Yutian volcanic cycle which occurs in middle Jurassic epoch is the bimodal rock association composed of rhyolite and basalt. Lianhuazhai volcanic cycle which occurs in late Jurassic epoch is unimodal rock association composed of rhyolite. Banshi volcanic cycle occurs from the late stage of early Cretaceous to the early stage of late Cretaceous epoch. There are two types of rock associations related to this cycle: unimodal rock association composed of rhyolite or basalt and bimodal rock association composed of rhyolite and basalt. Nanxiong volcanic activity cycle which occurred in late stage of late Cretaceous epoch is the unimodal rock association composed of basalt which is the interlayer of the red sedimentary series

Adsorption of 2,4-Dichlorophenoxyacetic Acid onto Volcanic Ash Soils:

Directory of Open Access Journals (Sweden)

Ei Ei Mon

2009-01-01

Full Text Available The quantification of the linear adsorption coefficient (Kd for soils plays a vital role to predict fate and transport of pesticides in the soil-water environment. In this study, we measured Kd values for 2,4-Dichlorophenoxyacetic acid (2,4-D adsorption onto Japanese volcanic ash soils with different amount of soil organic matter (SOM in batch experiments under different pH conditions. All measurements followed well both linear and Freundlich adsorption isotherms. Strong correlations were found between measured Kd values and pH as well as SOM. The 2,4-D adsorption increased with decreasing pH and with increasing SOM. Based on the data, a predictive Kd equation for volcanic ash soils, log (Kd = 2.04 - 0.37 pH + 0.91 log (SOM, was obtained by the multiple regression analysis. The predictive Kd equation was tested against measured 2,4-D sorption data for other volcanic ash soils and normal mineral soils from literature. The proposed Kd equation well predicted Kd values for other volcanic ash soils and slightly over- or under-predicted Kd values for normal mineral soils. The proposed Kd equation performed well against volcanic ash soils from different sites and countries, and is therefore recommended for predicting Kd values at different pH and SOM conditions for volcanic ash soils when calculating and predicting 2,4-D mobility and fate in soil and groundwater.

Volcanic ash impacts on critical infrastructure

Science.gov (United States)

Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

2012-01-01

Volcanic eruptions can produce a wide range of hazards. Although phenomena such as pyroclastic flows and surges, sector collapses, lahars and ballistic blocks are the most destructive and dangerous, volcanic ash is by far the most widely distributed eruption product. Although ash falls rarely endanger human life directly, threats to public health and disruption to critical infrastructure services, aviation and primary production can lead to significant societal impacts. Even relatively small eruptions can cause widespread disruption, damage and economic loss. Volcanic eruptions are, in general, infrequent and somewhat exotic occurrences, and consequently in many parts of the world, the management of critical infrastructure during volcanic crises can be improved with greater knowledge of the likely impacts. This article presents an overview of volcanic ash impacts on critical infrastructure, other than aviation and fuel supply, illustrated by findings from impact assessment reconnaissance trips carried out to a wide range of locations worldwide by our international research group and local collaborators. ‘Critical infrastructure’ includes those assets, frequently taken for granted, which are essential for the functioning of a society and economy. Electricity networks are very vulnerable to disruption from volcanic ash falls. This is particularly the case when fine ash is erupted because it has a greater tendency to adhere to line and substation insulators, where it can cause flashover (unintended electrical discharge) which can in turn cause widespread and disruptive outages. Weather conditions are a major determinant of flashover risk. Dry ash is not conductive, and heavy rain will wash ash from insulators, but light rain/mist will mobilise readily-soluble salts on the surface of the ash grains and lower the ash layer’s resistivity. Wet ash is also heavier than dry ash, increasing the risk of line breakage or tower/pole collapse. Particular issues for water

On a Possible Unified Scaling Law for Volcanic Eruption Durations.

Science.gov (United States)

Cannavò, Flavio; Nunnari, Giuseppe

2016-03-01

Volcanoes constitute dissipative systems with many degrees of freedom. Their eruptions are the result of complex processes that involve interacting chemical-physical systems. At present, due to the complexity of involved phenomena and to the lack of precise measurements, both analytical and numerical models are unable to simultaneously include the main processes involved in eruptions thus making forecasts of volcanic dynamics rather unreliable. On the other hand, accurate forecasts of some eruption parameters, such as the duration, could be a key factor in natural hazard estimation and mitigation. Analyzing a large database with most of all the known volcanic eruptions, we have determined that the duration of eruptions seems to be described by a universal distribution which characterizes eruption duration dynamics. In particular, this paper presents a plausible global power-law distribution of durations of volcanic eruptions that holds worldwide for different volcanic environments. We also introduce a new, simple and realistic pipe model that can follow the same found empirical distribution. Since the proposed model belongs to the family of the self-organized systems it may support the hypothesis that simple mechanisms can lead naturally to the emergent complexity in volcanic behaviour.

Io - One of at Least Four Simultaneous Erupting Volcanic Eruptions

Science.gov (United States)

1979-01-01

This photo of an active volcanic eruption on Jupiter's satellite Io was taken 1 hour, 52 minutes after the accompanying picture, late in the evening of March 4, 1979, Pacific time. On the limb of the satellite can be seen one of at least four simultaneous volcanic eruptions -- the first such activity ever observed on another celestial body. Seen against the limb are plume-like structures rising more than 60 miles (100 kilometers) above the surface. Several eruptions have been identified with volcanic structures on the surface of Io, which have also been identified by Voyager 1's infrared instrument as being abnormally hot -- several hundred degrees warmer than surrounding terrain. The fact that several eruptions appear to be occurring at the same time suggests that Io has the most active surface in the solar system and that volcanism is going on there essentially continuously. Another characteristic of the observed volcanism is that it appears to be extremely explosive, with velocities more than 2,000 miles an hour (at least 1 kilometer per second). That is more violent than terrestrial volcanoes like Etna, Vesuvius or Krakatoa.

Mapping Intraplate Volcanic Fields: A Case Study from Harrat Rahat, Saudi Arabia

Science.gov (United States)

Downs, D. T.; Stelten, M. E.; Champion, D. E.; Dietterich, H. R.

2017-12-01

Continental intraplate mafic volcanoes are typically small-volume (200 volcanic fields proposed to be active worldwide during the Holocene. Their small individual eruption volumes make any hazards low, however their high prevalence offsets this by raising the risk to populations and infrastructure. The western Arabian Plate hosts at least 15 continental, intra-plate volcanic fields that stretch >3,000 km south to north from Yemen to Turkey. In total, these volcanic fields comprise one of the largest alkali basalt volcanic provinces on Earth, covering an area of 180,000 km2. With a total volume of 20,000 km3, Harrat Rahat in western Saudi Arabia is one of the largest of these volcanic fields. Our study focused on mapping the northern third of the Harrat Rahat volcanic field using a multidisciplinary approach. We have discriminated >200 individual eruptive units, mainly basaltic lava flows throughout Harrat Rahat that are distinguished through a combination of field observations, petrography, geochemistry, paleomagnetism, and 40Ar/39Ar radiometric and 36Cl cosmogenic surface-exposure dating. We have compiled these results into a high-resolution geologic map, which provides new information about the timing, compositions, and eruptive processes of Quaternary volcanism in Harrat Rahat. For example, prior mapping and geochronology undertaken during the 1980s suggested that the majority of mafic and silicic volcanics erupted during the Miocene and Pliocene, whereas several of the youngest-appearing lava flows were interpreted to be Neolithic ( 7,000 to 4,500 years BP) to post-Neolithic. New mapping and age-constrained stratigraphic relations indicate that all exposed volcanic units within the northern third of Harrat Rahat erupted during the Pleistocene, with the exception of a single Holocene eruption in 1256 AD. This new multidisciplinary mapping is critical for understanding the overall spatial, temporal, and compositional evolution of Harrat Rahat, timescales of

Perspectivas Futuras para o Observatório do Pico dos Dias

Science.gov (United States)

Bruch, Albert

2004-02-01

Com o Observatório Gemini plenamente operacional e o telescópio SOAR iniciando suas operações em breve, a astronomia observacional brasileira encontra-se no auge de uma transformação profunda que terá um impacto grave no Observatório do Pico dos Dias - OPD. Refletimos aqui sobre a natureza desse impacto e estratégias para manter a competitividade do OPD. Não queremos apresentar receitas prontas, mas idéias que poderão servir como base de discussão sobre o uso inteligente dos telescópios do OPD como parte do conjunto de instrumentos disponíveis à comunidade astronômica brasileira.

Holocene volcanism of the upper McKenzie River catchment, central Oregon Cascades, USA

Science.gov (United States)

Deligne, Natalia I.; Conrey, Richard M.; Cashman, Katharine V.; Champion, Duane E.; Amidon, William H.

2016-01-01

To assess the complexity of eruptive activity within mafic volcanic fields, we present a detailed geologic investigation of Holocene volcanism in the upper McKenzie River catchment in the central Oregon Cascades, United States. We focus on the Sand Mountain volcanic field, which covers 76 km2 and consists of 23 vents, associated tephra deposits, and lava fields. We find that the Sand Mountain volcanic field was active for a few decades around 3 ka and involved at least 13 eruptive units. Despite the small total volume erupted (∼1 km3 dense rock equivalent [DRE]), Sand Mountain volcanic field lava geochemistry indicates that erupted magmas were derived from at least two, and likely three, different magma sources. Single units erupted from one or more vents, and field data provide evidence of both vent migration and reoccupation. Overall, our study shows that mafic volcanism was clustered in space and time, involved both explosive and effusive behavior, and tapped several magma sources. These observations provide important insights on possible future hazards from mafic volcanism in the central Oregon Cascades.

The use of Remote Sensing for the Study of the Relationships Between Tectonics and Volcanism

Science.gov (United States)

Chorowicz, J.; Dhont, D.; Yanev, Y.; Bardintzeff, J.

2004-12-01

Observations of geometric relationships between tectonics and volcanism is a fruitful approach in geology. On the one hand analysis of the distribution and types of volcanic vents provides information on the geodynamics. On the other hand tectonic analysis explains the location of volcanics vents. Volcanic edifices often result from regional scale deformation, forming open structures constituting preferred pathways for the rise of magmas. Analysis of the shape and the distribution of vents can consequently provide data on the regional deformation. Remote sensing imagery gives synoptic views of the earth surface allowing the analysis of landforms of still active tectonic and volcanic features. Shape and distribution of volcanic vents, together with recent tectonic patterns are best observed by satellite data and Digital Elevation Models than in the field. The use of radar scenes for the study of the structural relationships between tectonic and volcanic features is particularly efficient because these data express sensitive changes in the morphology. In various selected areas, we show that volcanic edifices are located on tension fractures responsible for fissure eruptions, volcanic linear clusters and elongate volcanoes. Different types of volcanic emplacements can be also distinguished such as tail-crack or horse-tail features, and releasing bend basins along strike-slip faults. Caldera complexes seem to be associated to horse-tail type fault terminations. At a regional scale, the distribution of volcanic vents and their relationships with the faults is able to explain the occurrence of volcanism in collisional areas.

Effects of volcanic deposit disaggregation on exposed water composition

Science.gov (United States)

Back, W. E.; Genareau, K. D.

2016-12-01

Explosive volcanic eruptions produce a variety of hazards. Pyroclastic material can be introduced to water through ash fallout, pyroclastic flows entering water bodies, and/or lahars. Remobilization of tephras can occur soon after eruption or centuries later, introducing additional pyroclastic material into the environment. Introduction of pyroclastic material may alter the dissolved element concentration and pH of exposed waters, potentially impacting drinking water supplies, agriculture, and ecology. This study focuses on the long-term impacts of volcanic deposits on water composition due to the mechanical breakup of volcanic deposits over time. Preliminary work has shown that mechanical milling of volcanic deposits will cause significant increases in dissolved element concentrations, conductivity, and pH of aqueous solutions. Pyroclastic material from seven eruptions sites was collected, mechanically milled to produce grain sizes Soufriere Hills, Ruapehu), mafic (Lathrop Wells) and ultramafic (mantle xenoliths) volcanic deposits. Lathrop Wells has an average bulk concentration of 49.15 wt.% SiO2, 6.11 wt. % MgO, and 8.39 wt. % CaO and produces leachate concentrations of 85.69 mg/kg for Ca and 37.22 mg/kg for Mg. Taupo and Valles Caldera samples have a bulk concentration of 72.9 wt.% SiO2, 0.59 wt. % MgO, and 1.48 wt. % CaO, and produces leachate concentrations of 4.08 mg/kg for Ca and 1.56 mg/kg for Mg. Similar testing will be conducted on the intermediate and ultramafic samples to test the hypothesis that bulk magma composition and mineralogy will directly relate to the increased dissolved element concentration of exposed waters. The measured effects on aqueous solutions will aid in evaluation of impacts to marine and freshwater systems exposed to volcanic deposits.

'Cerrásteme la puerta rigurosa': exclusus amator, un tópico clásico en las letras españolas

Directory of Open Access Journals (Sweden)

Ramajo Caño, Antonio

2004-12-01

Full Text Available The commonplace of the exclusus amator first arose in ancient Greece. Refashioned again and again in Latin literature, it came into Spanish literature, where it was to appear with a certain frequency until well into Romanticism. The present work points out texts where it appears and shows how it has changed and how it has remained the same.El tópico del exclusus amator brota en la Grecia arcaica. Reelaborado una y otra vez en la literatura latina, llegará a la literatura española, en la que aparecerá con cierta frecuencia, al menos hasta entrado el Romanticismo. En el presente trabajo se señalan textos donde el tópico figura, con su permanencia y su variación.

Analysis of volcanic tephra as a material of environment

Science.gov (United States)

Sitek, J.; Dekan, J.; Fang, X.; Xiaoli, P.; Chmielewská, E.

2012-10-01

Tephra is a fragmental material produced by volcanic eruption. Here, volcanic tephra deposit from the northeast of China was used for our study. Samples of unaltered tephra are usually composed of feldspar, glass, pyroxene, and olivine. Moreover, these volcanic alteration products also contain Fe oxides, phylosilicates, sulfates, and amorphous Al-Si-bearing material. Six different samples of tephra obtained were analyzed by Mössbauer spectroscopy. A typical Mössbauer spectrum of tephra consists of magnetic and non-magnetic components (magnetic component represents about 11% and non-magnetic component about 89% of spectral area). According to the structural composition, it may be supposed that the magnetic component can be assigned to titanomagnetite. Non-magnetic components contain two quadrupole doublets (Fe2+ species) and one doublet containing Fe3+. According to the measured values of Mössbauer spectra, the first two doublets are very similar with pyroxene, olivine and the third to phylosilicate, aluminosilicate or iron oxide of FeO type. Recently, volcanic tephra was applied as an ecological substance. Special solution was proposed for tephra utilization, especially for phosphate removal from contaminated water.

Natural radioactivity in volcanic ash from Mt. Pinatubo eruption

International Nuclear Information System (INIS)

Duran, E.B.; De Vera, C.M.; Garcia, T.Y.; Dela Cruz, F.M.; Esguerra, L.V.; Castaneda, S.S.

1992-01-01

Last June 15, 1991, a major pyroclastic eruption occurred from Mt. Pinatubo volcano located in Zambales, Central Luzon. The radiological impact of this eruption was assessed based on the concentrations of the principal naturally occurring radionuclides observed in volcanic ash. The volcanic ash samples were collected from locations which are within 50-km radius of Mt. Pinatubo at various times after the eruption. The mean activity concentrations in Bq/kg wet weight of the natural radionuclides in volcanic ash were as follows: 12.6 for 238 U, 14.0 for 232 Th and 330 for 40 K. These values are significantly higher than the mean activity concentrations of these radionuclides observed in topsoil in the same provinces before the eruption. This suggests that with the deposition of large quantities of volcanic ash and lahar in Central Luzon and concomitant topographic changes, the distribution and quantities of radionuclides which gave rise to terrestrial radiation may have also changed. Outdoor radon concentrations measured three days and later after the eruption were within normal background values. (auth.). 4 refs.; 5 tabs.; 1 fig

Permeability of volcanic rocks to gas and water

Science.gov (United States)

Heap, M. J.; Reuschlé, T.; Farquharson, J. I.; Baud, P.

2018-04-01

The phase (gas or liquid) of the fluids within a porous volcanic system varies in both time and space. Laboratory experiments have shown that gas and water permeabilities can differ for the same rock sample, but experiments are biased towards rocks that contain minerals that are expected react with the pore fluid (such as the reaction between liquid water and clay). We present here the first study that systematically compares the gas and water permeability of volcanic rocks. Our data show that permeabilities to argon gas and deionised water can differ by a factor between two and five in two volcanic rocks (basalt and andesite) over a confining pressure range from 2 to 50 MPa. We suggest here that the microstructural elements that offer the shortest route through the sample-estimated to have an average radius 0.1-0.5 μm using the Klinkenberg slip factor-are accessible to gas, but restricted or inaccessible to water. We speculate that water adsorption on the surface of these thin microstructural elements, assumed here to be tortuous/rough microcracks, reduces their effective radius and/or prevents access. These data have important implications for fluid flow and therefore the distribution and build-up of pore pressure within volcanic systems.

Role of Social Media and Networking in Volcanic Crises and Communication

Science.gov (United States)

Sennert, S.; Klemetti, E. W.; Bird, D. K.

2016-12-01

The growth of social media as a primary and often preferred news source has led to the rapid dissemination of information about volcanic eruptions and potential volcanic crises as they begin, evolve, and end. This information comes from a variety of sources: news organisations, emergency management personnel, individuals (both members of the public and official representatives), and volcano monitoring agencies. Once posted, this information is easily shared, increasing the reach to a much broader population than more traditional forms of media, such as radio and newspapers. The onset and popularity of social media as a vehicle for dissemination of eruption information points toward the need to systematically incorporate social media into the official channels that volcano observatories use to distribute activity statements, forecasts, and images. We explore two examples of projects that collect/disseminate information regarding volcanic crises and eruptive activity via social media sources; the Smithsonian/USGS Weekly Volcanic Activity Report (WVAR), which summarizes new and on-going volcanic activity globally and on a weekly basis, and Eruptions, a blog that discusses eruptions as well as other volcanic topics. Based on these experiences, recommendations are made to volcanic observatories in relation to the use of social media as a communication tool. These recommendations include: using social media as a two-way dialogue to communicate and receive information directly from the public and other sources; stating that the social media account is from an official source; and posting types of information that users want to see such as images, videos, and figures.

Acidic volcanic rock and its potential as an objective for uranium prospecting

International Nuclear Information System (INIS)

Rodriguez Torres, R.; Yza Dominguez, R.; Chavez Aguirre, R.; Constantino, H.E.S.E.

1976-01-01

The geographical distribution of recent Mexican volcanic rocks is continuous; the older formations are dispersed in isolated outcrops. Continental volcanic events, acidic and basal, took place in the Caenozoic, Mesozoic and Palaeozoic; basic submarine volcanism predominated in the Mesozoic, Palaeozoic and late Precambrian. Access to the Sierra Madre Occidental, a circum-Pacific mountain range covered by rhyolitic rocks, is limited, which restricts the sections studied. Calderas, sources of volcanic emission and preliminary litho-stratigraphic sections have been delimited on the eastern edge of the range. Subduction by the ocean magmatized the continent from the Permian onwards, extravasating and depositing cyclically various magmata through inverted and normal cortical throws. The Sierra Pena Blanca (Chihuahua) section consists of epiclastic and pyroclastic rocks. A calcareous conglomerate is overburdened by alternate basal tuffs and imbricates, forming five units. In the uraniferous district of the Sierra Pena Blanca the hydrothermal alteration argillitized both components of the ''Nopal'' formation. Primary minerals (pitchblende) are found together with silicification. Leaching favours secondary mineralization (uranium silicates) associated with opals. After extrapolation of the features, the following are considered worth-while objectives: the faces, offsets and prolongations of the Sierra Madre Occidental and the southern volcanic mesetas south of the Mexican Transcontinental Rift. Similar objectives of Mesozoic or Palaeozoic age exist in central and southern Mexico. Possible objectives for uranium are: the acidic volcanic rock of the southern and south-western United States of America, the circum-Pacific acidic volcanic rocks of North America and the acidic volcanic mesetas of Central America and in the Andes. (author)

Uma Abordagem ao Págico baseada no Processamento e Análise de Sintagmas dos Tópicos

Directory of Open Access Journals (Sweden)

Ricardo Rodrigues

2012-04-01

Full Text Available Este artigo descreve a abordagem ao Págico seguida pelo sistema Rapportágico. Trata-se de uma abordagem centrada na indexação dos artigos da Wikipédia, na identificação de sintagmas nas frases dos tópicos dados, e no seu posterior processamento e análise, de forma a facilitar a correspondência entre tópicos e artigos que lhes possam servir de resposta. Os sintagmas facilitam a identificação de pequenas estruturas com diferentes papéis dentro da frase. Antes de serem utilizados para consulta, alguns sintagmas sofrem manipulações, como, por exemplo, a expansão das palavras que os constituem em palavras de significado semelhante (sinónimos. Embora haja ainda um longo caminho a percorrer, o sucesso da abordagem traduziu-se, em termos de resultados, na obtenção de uma pontuação com algum destaque entre todas as participações no Págico, especialmente naquelas automáticas.

Modeling volcanic ash dispersal

CERN Multimedia

CERN. Geneva

2010-01-01

The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard...

Combining probabilistic hazard assessment with cost-benefit analysis to support decision making in a volcanic crisis from the Auckland Volcanic Field, New Zealand

Science.gov (United States)

Sandri, Laura; Jolly, Gill; Lindsay, Jan; Howe, Tracy; Marzocchi, Warner

2010-05-01

One of the main challenges of modern volcanology is to provide the public with robust and useful information for decision-making in land-use planning and in emergency management. From the scientific point of view, this translates into reliable and quantitative long- and short-term volcanic hazard assessment and eruption forecasting. Because of the complexity in characterizing volcanic events, and of the natural variability of volcanic processes, a probabilistic approach is more suitable than deterministic modeling. In recent years, two probabilistic codes have been developed for quantitative short- and long-term eruption forecasting (BET_EF) and volcanic hazard assessment (BET_VH). Both of them are based on a Bayesian Event Tree, in which volcanic events are seen as a chain of logical steps of increasing detail. At each node of the tree, the probability is computed by taking into account different sources of information, such as geological and volcanological models, past occurrences, expert opinion and numerical modeling of volcanic phenomena. Since it is a Bayesian tool, the output probability is not a single number, but a probability distribution accounting for aleatory and epistemic uncertainty. In this study, we apply BET_VH in order to quantify the long-term volcanic hazard due to base surge invasion in the region around Auckland, New Zealand's most populous city. Here, small basaltic eruptions from monogenetic cones pose a considerable risk to the city in case of phreatomagmatic activity: evidence for base surges are not uncommon in deposits from past events. Currently, we are particularly focussing on the scenario simulated during Exercise Ruaumoko, a national disaster exercise based on the build-up to an eruption in the Auckland Volcanic Field. Based on recent papers by Marzocchi and Woo, we suggest a possible quantitative strategy to link probabilistic scientific output and Boolean decision making. It is based on cost-benefit analysis, in which all costs

Diagnóstico fenotípico de las inmunodeficiencias primarias en Antioquia, Colombia, 1994-2002.

Directory of Open Access Journals (Sweden)

Carlos Julio Montoya

2002-12-01

Full Text Available La infección recurrente es una causa frecuente de consulta médica y puede deberse a un grupo heterogéneo de trastornos que incrementan la susceptibilidad a los microorganismos patógenos y oportunistas, como las deficiencias inmunológicas subyacentes. Con el fin de definir un tratamiento racional oportuno y orientar el diagnóstico molecular de las inmunodeficiencias primarias, se estableció un programa para el diagnóstico fenotípico de estas enfermedades en el departamento de Antioquia (Colombia, que comprende un análisis clínico y de laboratorio de los individuos que presentan infecciones recurrentes de evolución anormal. Entre el 1 de agosto de 1994 y el 31 de julio de 2002 se hizo el diagnóstico fenotípico de inmunodeficiencia primaria en 98 pacientes. Similar a lo informado en la literatura especializada, en esta región las deficiencias predominantes de anticuerpos fueron las más frecuentes (40,8% seguidas por las deficiencias combinadas (21,4%. Esta caracterización fenotípica ha permitido iniciar rápidamente el tratamiento adecuado y, en algunos casos, comenzar los estudios funcionales y moleculares que conduzcan al diagnóstico molecular definitivo.

Sedimentary response to volcanic activity in the Okinawa Trough since the last deglaciation

Institute of Scientific and Technical Information of China (English)

蒋富清; 李安春; 李铁刚

2010-01-01

To investigate the relationship between volcanic activity and sediment record on regional and temporal scales,158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (OT),and two cores recovered in the northern and southern OT,respectively.Mineralogy,grain-size,and geochemical analyses of those samples show that:1) volcanic glass,volcanic-type pyroxene,hypersthenes,and magnetite increase in sediment influenced by volcanic activity;2) sediment grain sizes (and...

Volcanic Ash from the 1999 Eruption of Mount Cameroon Volcano ...

African Journals Online (AJOL)

2008-10-21

Oct 21, 2008 ... fluorine (F) content of the ash was determined by the selective ion electrode method. The results ... the main mineral in volcanic ash responsible for causing silicosis. The F ... volcanic ash with little or no attention to the < 4 µm.

Global Volcanism on Mercury at About 3.8 Ga

Science.gov (United States)

Byrne, P. K.; Ostrach, L. R.; Denevi, B. W.; Head, J. W., III; Hauck, S. A., II; Murchie, S. L.; Solomon, S. C.

2014-12-01

Smooth plains occupy c. 27% of the surface of Mercury. Embayment relations, spectral contrast with surroundings, and morphologic characteristics indicate that the majority of these plains are volcanic. The largest deposits are located in Mercury's northern hemisphere and include the extensive northern plains (NP) and the Caloris interior and exterior plains (with the latter likely including basin material). Both the NP and Caloris deposits are, within statistical error, the same age (~3.8-3.9 Ga). To test whether this age reflects a period of global volcanism on Mercury, we determined crater size-frequency distributions for four smooth plains units in the planet's southern hemisphere interpreted to be volcanic. Two deposits are situated within the Beethoven and Tolstoj impact basins; two are located close to the Debussy and the Alver and Disney basins, respectively. Each deposit hosts two populations of craters, one that postdates plains emplacement and one that consists of partially to nearly filled craters that predate the plains. This latter population indicates that some time elapsed between formation of the underlying basement and plains volcanism, though we cannot statistically resolve this interval at any of the four sites. Nonetheless, we find that the age given by the superposed crater population in each case is ~3.8 Ga, and crater density values are consistent with those for the NP and Caloris plains. This finding supports a global phase of volcanism near the end of the late heavy bombardment of Mercury and may indicate a period of widespread partial melting of Mercury's mantle. Notably, superposition relations between smooth plains, degraded impact structures, and contractional landforms suggest that by this time interior cooling had already placed Mercury's lithosphere in horizontal compression, tending to inhibit voluminous dike-fed volcanism such as that inferred responsible for the NP. Most smooth plains units, including the Caloris plains and our

Interaction between climate, volcanism, and isostatic rebound in Southeast Alaska during the last deglaciation

Science.gov (United States)

Praetorius, Summer; Mix, Alan; Jensen, Britta; Froese, Duane; Milne, Glenn A.; Wolhowe, Matthew; Addison, Jason A.; Prahl, Fred

2016-01-01

Observations of enhanced volcanic frequency during the last deglaciation have led to the hypothesis that ice unloading in glaciated volcanic terrains can promote volcanism through decompression melting in the shallow mantle or a reduction in crustal magma storage time. However, a direct link between regional climate change, isostatic adjustment, and the initiation of volcanism remains to be demonstrated due to the difficulty of obtaining high-resolution well-dated records that capture short-term climate and volcanic variability traced to a particular source region. Here we present an exceptionally resolved record of 19 tephra layers paired with foraminiferal oxygen isotopes and alkenone paleotemperatures from marine sediment cores along the Southeast Alaska margin spanning the last deglacial transition. Major element compositions of the tephras indicate a predominant source from the nearby Mt. Edgecumbe Volcanic Field (MEVF). We constrain the timing of this regional eruptive sequence to 14.6–13.1 ka. The sudden increase in volcanic activity from the MEVF coincides with the onset of Bølling–Allerød interstadial warmth, the disappearance of ice-rafted detritus, and rapid vertical land motion associated with modeled regional isostatic rebound in response to glacier retreat. These data support the hypothesis that regional deglaciation can rapidly trigger volcanic activity. Rapid sea surface temperature fluctuations and an increase in local salinity (i.e., δ18Osw) variability are associated with the interval of intense volcanic activity, consistent with a two-way interaction between climate and volcanism in which rapid volcanic response to ice unloading may in turn enhance short-term melting of the glaciers, plausibly via albedo effects on glacier ablation zones.

GM`s PICOS initiative on resource conservation and pollution prevention: Greening the supply chain

Energy Technology Data Exchange (ETDEWEB)

Pritchett, T. [General Motors Corp., Detroit, MI (United States)

1997-12-31

This paper is comprised of reprints of several related articles from business publications. The first article, on supply-side economics, describes efforts by General Motors to cut costs by encouraging suppliers to reduce the environmental impacts of their products. The PICOS{trademark} program of General Motors helps industrial identify and implement energy efficiency and pollution prevention projects that lower operating costs while reducing emissions linked to global climate change. The second article also describes the program, focusing on aspects of global competition.

MEVTV Workshop on Early Tectonic and Volcanic Evolution of Mars

International Nuclear Information System (INIS)

Frey, H.

1988-01-01

Although not ignored, the problems of the early tectonic and volcanic evolution of Mars have generally received less attention than those later in the evolution of the planet. Specifically, much attention was devoted to the evolution of the Tharsis region of Mars and to the planet itself at the time following the establishment of this major tectonic and volcanic province. By contrast, little attention was directed at fundamental questions, such as the conditions that led to the development of Tharsis and the cause of the basic fundamental dichotomy of the Martian crust. It was to address these and related questions of the earliest evolution of Mars that a workshop was organized under the auspices of the Mars: Evolution of Volcanism, Tectonism, and Volatiles (MEVTV) Program. Four sessions were held: crustal dichotomy; crustal differentiation/volcanism; Tharsis, Elysium, and Valles Marineris; and ridges and fault tectonics

Center for Volcanic and Tectonic Studies: 1992--1993 annual report

International Nuclear Information System (INIS)

1994-01-01

The annual report of the Center for Volcanic Studies (CVTS) contains a series of papers, reprints and a Master of Science thesis that review the progress made by the CVTS between October 1, 1992 and February 1, 1994. During this period CVTS staff focused on several topics that have direct relevance to volcanic hazards related to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. These topics include: (1) polygenetic/polycyclic volcanism in Crater Flat, Nevada; (2) the role of the mantle during crustal extension; (3) the detailed geology of Crater Flat, Nevada; (4) Pliocene volcanoes in the Reveille Range, south-central Nevada; (5) estimating the probability of disruption of the proposed repository by volcanic eruptions. This topic is being studied by Dr. C.H. Ho at UNLV. The report contains copies of these individual papers as they were presented in various conference proceedings

Obsidian hydration dating of volcanic events

Science.gov (United States)

Friedman, I.; Obradovich, J.

1981-01-01

Obsidian hydration dating of volcanic events had been compared with ages of the same events determined by the 14C and KAr methods at several localities. The localities, ranging in age from 1200 to over 1 million yr, include Newberry Craters, Oregon; Coso Hot Springs, California; Salton Sea, California; Yellowstone National Park, Wyoming; and Mineral Range, Utah. In most cases the agreement is quite good. A number of factors including volcanic glass composition and exposuretemperature history must be known in order to relate hydration thickness to age. The effect of composition can be determined from chemical analysis or the refractive index of the glass. Exposure-temperature history requires a number of considerations enumerated in this paper. ?? 1981.

Seasonal variations of volcanic eruption frequencies

Science.gov (United States)

Stothers, Richard B.

1989-01-01

Do volcanic eruptions have a tendency to occur more frequently in the months of May and June? Some past evidence suggests that they do. The present study, based on the new eruption catalog of Simkin et al.(1981), investigates the monthly statistics of the largest eruptions, grouped according to explosive magnitude, geographical latitude, and year. At the 2-delta level, no month-to-month variations in eruption frequency are found to be statistically significant. Examination of previously published month-to-month variations suggests that they, too, are not statistically significant. It is concluded that volcanism, at least averaged over large portions of the globe, is probably not periodic on a seasonal or annual time scale.

The volcanic rocks construction of the late paleozoic era and uranium mineralization in Beishan area of Gansu province

International Nuclear Information System (INIS)

An Zhengchang; Luo Xiaoqiang

2010-01-01

Late Paleozoic volcanic rocks in Beishan area are the favorable constructions of hydrothermal type and volcanic type deposit. From the distribution of volcanic rocks, the volcanic compositions, the volcanic facies, volcanic eruption method and rhythm, chemical and trace elements compositions, and so on, it discusses the characteristics of the Late Devonian volcanic construction in this area and its relationship with uranium mineralization, analyzes the role of volcanic ore-control mechanism, and summarizes uranium ore forming regularity of volcanic construction in Late Paleozoic. (authors)

Applying geophysical surveys for studying subsurface geology of monogenetic volcanic fields: the example of La Garrotxa Volcanic Field (NE of Iberian Peninsula)

Science.gov (United States)

Bolós, Xavier; Barde-Cabusson, Stéphanie; Pedrazzi, Dario; Martí, Joan; Casas, Albert; Lovera, Raúl; Nadal-Sala, Daniel

2014-05-01

Improving knowledge of the shallowest part of the feeding system of monogenetic volcanoes and the relationship with the subsurface geology is an important task. We applied high-precision geophysical techniques that are self-potential and electrical resistivity tomography, for the exploration of the uppermost part of the substrate of La Garrotxa Volcanic Field, which is part of the European Cenozoic Rift System. Previous geophysical studies carried out in the same area at a less detailed scale were aimed at identifying deeper structures, and together constitute the basis to establish volcanic susceptibility in La Garrotxa. Self-potential study allowed identifying key areas where electrical resistivity tomography could be conducted. Dykes and faults associated with several monogenetic cones were identified through the generation of resistivity models. The combined results confirm that shallow tectonics controlling the distribution of the foci of eruptive activity in this volcanic zone mainly correspond to NNW-SSE and accessorily by NNE-SSW Neogene extensional fissures and faults and concretely show the associated magmatic intrusions. These studies show that previous alpine tectonic structures played no apparent role in controlling the loci of this volcanism. Furthermore, the results obtained show that the changes in eruption dynamics occurring at different vents located at relatively short distances in this volcanic area can be controlled by shallow stratigraphical, structural, and hydrogeological features underneath these monogenetic volcanoes. This study was partially funded by the Beca Ciutat d'Olot en Ciències Naturals and the European Commission (FT7 Theme: ENV.2011.1.3.3-1; Grant 282759: "VUELCO").

Validación de dos algoritmos para la localización 3D del instrumental laparoscópico a partir de la imagen de vídeo endoscópico

OpenAIRE

Oropesa García, Ignacio; Sánchez González, Patricia; Morales Martín, Iñigo; Moyano Cuevas, J.L.; Sánchez Margallo, Francisco Miguel; Gómez Aguilera, Enrique J.

2012-01-01

Uno de los aspectos fundamentales en un sistema de cirugía guiada por imagen (CGI) es la localización del instrumental quirúrgico con respecto a la anatomía del paciente. Los sistemas basados en sensores ofrecen buenos niveles de precisión, pero son sensibles a distintas fuentes de ruido en el quirófano y contribuyen a la sobrecarga tecnológica del mismo. Una alternativa novedosa es analizar la imagen del vídeo endoscópico para llevar a cabo la detección y localización espacial del instrument...

Volcanism in slab tear faults is larger than in island-arcs and back-arcs.

Science.gov (United States)

Cocchi, Luca; Passaro, Salvatore; Tontini, Fabio Caratori; Ventura, Guido

2017-11-13

Subduction-transform edge propagators are lithospheric tears bounding slabs and back-arc basins. The volcanism at these edges is enigmatic because it is lacking comprehensive geological and geophysical data. Here we present bathymetric, potential-field data, and direct observations of the seafloor on the 90 km long Palinuro volcanic chain overlapping the E-W striking tear of the roll-backing Ionian slab in Southern Tyrrhenian Sea. The volcanic chain includes arc-type central volcanoes and fissural, spreading-type centers emplaced along second-order shears. The volume of the volcanic chain is larger than that of the neighbor island-arc edifices and back-arc spreading center. Such large volume of magma is associated to an upwelling of the isotherms due to mantle melts upraising from the rear of the slab along the tear fault. The subduction-transform edge volcanism focuses localized spreading processes and its magnitude is underestimated. This volcanism characterizes the subduction settings associated to volcanic arcs and back-arc spreading centers.

Volcanic risk; Risque volcanique

Energy Technology Data Exchange (ETDEWEB)

Rancon, J.P.; Baubron, J.C.

1995-12-31

This project follows the previous multi-disciplinary studies carried out by the French Bureau de Recherches Geologiques et Minieres (BRGM) on the two active volcanoes of the French lesser Antilles: Mt Pelee (Martinique) and Soufriere (Guadeloupe) for which geological maps and volcanic risk studies have been achieved. The research program comprises 5 parts: the study of pyroclastic deposits from recent eruptions of the two volcanoes for a better characterization of their eruptive phenomenology and a better definition of crisis scenarios; the study of deposits and structures of active volcanoes from Central America and the study of eruptive dynamics of andesite volcanoes for a transposition to Antilles` volcanoes; the starting of a methodological multi-disciplinary research (volcanology, geography, sociology...) on the volcanic risk analysis and on the management of a future crisis; and finally, the development of geochemical survey techniques (radon, CO{sub 2}, H{sub 2}O) on active volcanoes of Costa-Rica and Europe (Fournaise, Furnas, Etna) and their application to the Soufriere. (J.S.). 9 refs., 3 figs.

Volcanic influence on centennial to millennial Holocene Greenland temperature change.

Science.gov (United States)

Kobashi, Takuro; Menviel, Laurie; Jeltsch-Thömmes, Aurich; Vinther, Bo M; Box, Jason E; Muscheler, Raimund; Nakaegawa, Toshiyuki; Pfister, Patrik L; Döring, Michael; Leuenberger, Markus; Wanner, Heinz; Ohmura, Atsumu

2017-05-03

Solar variability has been hypothesized to be a major driver of North Atlantic millennial-scale climate variations through the Holocene along with orbitally induced insolation change. However, another important climate driver, volcanic forcing has generally been underestimated prior to the past 2,500 years partly owing to the lack of proper proxy temperature records. Here, we reconstruct seasonally unbiased and physically constrained Greenland Summit temperatures over the Holocene using argon and nitrogen isotopes within trapped air in a Greenland ice core (GISP2). We show that a series of volcanic eruptions through the Holocene played an important role in driving centennial to millennial-scale temperature changes in Greenland. The reconstructed Greenland temperature exhibits significant millennial correlations with K + and Na + ions in the GISP2 ice core (proxies for atmospheric circulation patterns), and δ 18 O of Oman and Chinese Dongge cave stalagmites (proxies for monsoon activity), indicating that the reconstructed temperature contains hemispheric signals. Climate model simulations forced with the volcanic forcing further suggest that a series of large volcanic eruptions induced hemispheric-wide centennial to millennial-scale variability through ocean/sea-ice feedbacks. Therefore, we conclude that volcanic activity played a critical role in driving centennial to millennial-scale Holocene temperature variability in Greenland and likely beyond.

Systematic change in global patterns of streamflow following volcanic eruptions.

Science.gov (United States)

Iles, Carley E; Hegerl, Gabriele C

2015-11-01

Following large explosive volcanic eruptions precipitation decreases over much of the globe1-6, particularly in climatologically wet regions4,5. Stratospheric volcanic aerosols reflect sunlight, which reduces evaporation, whilst surface cooling stabilises the atmosphere and reduces its water-holding capacity7. Circulation changes modulate this global precipitation reduction on regional scales1,8-10. Despite the importance of rivers to people, it has been unclear whether volcanism causes detectable changes in streamflow given large natural variability. Here we analyse observational records of streamflow volume for fifty large rivers from around the world which cover between two and 6 major volcanic eruptions in the 20 th and late 19 th century. We find statistically significant reductions in flow following eruptions for the Amazon, Congo, Nile, Orange, Ob, Yenisey and Kolyma amongst others. When data from neighbouring rivers are combined - based on the areas where climate models simulate either an increase or a decrease in precipitation following eruptions - a significant (peruptions is detected in northern South American, central African and high-latitude Asian rivers, and on average across wet tropical and subtropical regions. We also detect a significant increase in southern South American and SW North American rivers. This suggests that future volcanic eruptions could substantially affect global water availability.

Germinomas cerebrais (teratomas atípicos da pineal Cerebral germinomas (atipical teratomas of the pineal region

Directory of Open Access Journals (Sweden)

Alexandre Alencar

1981-12-01

Full Text Available São estudados três casos de germinomas cerebrais, sendo um tópico, da região pineal, e dois ectópicos, chamados germinomas supra-selares ou quiasmáticos. Estes últimos parecem ser mais agressivos que os seus congeneres tópicos, pois alem de se disseminarem pelas cisternas basais, costumam infiltrar as paredes do III ventrículo, fórnix, hipotálamo, nervos e quiasma ópticos. Caracteristicamente produzem um enorme aumento das proteínas liquóricas, desacompanhado de uma pleocitose proporcional. As proteínas liquóricas aumentadas sao globulinas cujas reações mostram-se fortemente positivas, possivelmente produzidas pelas celulas de aspecto linfocitario que constituem parte desta neoplasia. O aumento das proteinas liquoricas e tao acentuado que em presenca de uma crianca ou adolescente com sindrome de hipertensão intracraniana, hiperproteinoraquia sem pleocitose e sinais clínicos ou radiológicos sugestivos de localização na base do crânio a possibilidade de um germinoma quiasmático deve ser seriamente considerada, pois o quadro e muito sugestivo.Three cases of Cerebral Germinomas, one of them situated in the pineal region (topical and two ectopical of the so called suprasellar or chiasmal Germinomas are studied. These last ones may be more aggressive than the congeneral topical ones, since besides it's dissemination throughout the basal cisternas they usually infilstrate into de walls of the III Ventricle, Fornix, Hypothalamus, Chiasma and Optic nervs. A high level of proteins in the spinal fluid without proportional increase of the cells is characteristic. Globulins are the predominant fraction of the increased spinal fluid proteins, as indicated by the highly positive laboratory test. These globulins are possibly produced by the lymphocytes which are part of this neoplasm. The high level of protein in the spinal fluid without proportional increase of the cells, in the presence of intracranial syndrome in a child or

The structural architecture of the Los Humeros volcanic complex and geothermal field, Trans-Mexican Volcanic Belt, Central Mexico

Science.gov (United States)

Norini, Gianluca; Groppelli, Gianluca; Sulpizio, Roberto; Carrasco Núñez, Gerardo; Davila Harris, Pablo

2014-05-01

The development of geothermal energy in Mexico is a very important goal, given the presence of a large heat anomaly, associated with the Trans-Mexican Volcanic Belt, the renewability of the resource and the low environmental impact. The Quaternary Los Humeros volcanic complex is an important geothermal target, whose evolution involved at least two caldera events, that alternated with other explosive and effusive activity. The first caldera forming event was the 460 ka eruption that produced the Xaltipan ignimbrite and formed a 15-20 km wide caldera. The second collapse event occurred 100 ka with the formation of the Zaragoza ignimbrite and a nested 8-10 km wide caldera. The whole volcano structure, the style of the collapses and the exact location of the calderas scarps and ring faults are still a matter of debate. The Los Humeros volcano hosts the productive Los Humeros Geothermal Field, with an installed capacity of 40 MW and additional 75 MW power plants under construction. Recent models of the geothermal reservoir predict the existence of at least two reservoirs in the geothermal system, separated by impermeable rock units. Hydraulic connectivity and hydrothermal fluids circulation occurs through faults and fractures, allowing deep steam to ascend while condensate flows descend. As a consequence, the plans for the exploration and exploitation of the geothermal reservoir have been based on the identification of the main channels for the circulation of hydrothermal fluids, constituted by faults, so that the full comprehension of the structural architecture of the caldera is crucial to improve the efficiency and minimize the costs of the geothermal field operation. In this study, we present an analysis of the Los Humeros volcanic complex focused on the Quaternary tectonic and volcanotectonics features, like fault scarps and aligned/elongated monogenetic volcanic centres. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of

Seismic equivalents of volcanic jet scaling laws and multipoles in acoustics

Science.gov (United States)

Haney, Matthew M.; Matoza, Robin S.; Fee, David; Aldridge, David F.

2018-04-01

We establish analogies between equivalent source theory in seismology (moment-tensor and single-force sources) and acoustics (monopoles, dipoles and quadrupoles) in the context of volcanic eruption signals. Although infrasound (acoustic waves volcanic eruptions may be more complex than a simple monopole, dipole or quadrupole assumption, these elementary acoustic sources are a logical place to begin exploring relations with seismic sources. By considering the radiated power of a harmonic force source at the surface of an elastic half-space, we show that a volcanic jet or plume modelled as a seismic force has similar scaling with respect to eruption parameters (e.g. exit velocity and vent area) as an acoustic dipole. We support this by demonstrating, from first principles, a fundamental relationship that ties together explosion, torque and force sources in seismology and highlights the underlying dipole nature of seismic forces. This forges a connection between the multipole expansion of equivalent sources in acoustics and the use of forces and moments as equivalent sources in seismology. We further show that volcanic infrasound monopole and quadrupole sources exhibit scalings similar to seismicity radiated by volume injection and moment sources, respectively. We describe a scaling theory for seismic tremor during volcanic eruptions that agrees with observations showing a linear relation between radiated power of tremor and eruption rate. Volcanic tremor over the first 17 hr of the 2016 eruption at Pavlof Volcano, Alaska, obeyed the linear relation. Subsequent tremor during the main phase of the eruption did not obey the linear relation and demonstrates that volcanic eruption tremor can exhibit other scalings even during the same eruption.

40Ar/39Ar and K-Ar dating of altered glassy volcanic rocks: the Dabi Volcanics, P.N.G

International Nuclear Information System (INIS)

Walker, D.A.; McDougall, I.

1982-01-01

K-Ar and 40 Ar/ 39 Ar ages have been determined for altered submarine tholeiitic and boninite (high-Mg andesite) lavas from the Dabi Volcanics, Cape Vogel Peninsula, Papua New Guinea. 40 Ar/ 39 Ar whole rock total fusion and plateau ages identify a Late Paleocene age for the tholeiitic lavas (58.9 +- 1.1 Ma), and also for the boninitic lavas (58.8 +- 0.8 Ma). Apparent K-Ar ages for the same samples range from 27.2 +- 0.7 to 63.9 +- 4.5 Ma, and young K-Ar ages for glassy boninites are probably due to variable radiogenic 40 Ar( 40 Ar*) loss. These new ages effectively reconcile previously ambiguous age data for the Dabi Volcanics, and indicate contemporaneous tholeiitic and boninitic volcanism occurring in southeast PNG during the Late Paleocene. Smectites, developed as alteration products after glass in oceanic lavas commonly do not retain 39 Ar during or subsequent to irradiation, but in some cases may contain 40 Ar*. The results are discussed. (author)

PYROCLASTIC FLOW MODELING TO RECONSTRUCT A VOLCANIC EDIFICE IN PAIPA (BOYACÁ-COLOMBIA.

Directory of Open Access Journals (Sweden)

Rodríguez Óscar

2004-06-01

Full Text Available Pyroclastic deposits produced by the domes collapse (resurgence of a caldera collapse, at the west of the Honda Grande creek (Paipa, Boyacá-Colombia were related by INGEOMINAS. These deposits fill the valleys of Olitas, Calderitas and a creek at the south of the Alto de los Volcanes reaching distances near to 3 km from the focus between the Alto de los Volcanes and El Mirador Hill.The flows were modeled using 3D Software (Sheridan and Kover, 1996. A volcanic simulation was done obtaining the height and morphology of the volcanic edifice before the collapse during the last eruptive event.

Volcanic rises on Venus: Geology, formation, and sequence of evolution

Science.gov (United States)

Senske, D. A.; Stofan, E. R.; Bindschadler, D. L.; Smrekar, S. E.

1993-01-01

Large centers of volcanism on Venus are concentrated primarily in the equatorial region of the planet and are associated with regional topographic rises. Analysis of both radar images and geophysical data suggest that these uplands are sites of mantle upwelling. Magellan radar imaging provides a globally contiguous data set from which the geology of these regions is evaluated and compared. In addition, high resolution gravity data currently being collected provide a basis to assess the relationship between these uplands and processes in the planet's interior. Studies of the geology of the three largest volcanic highlands (Beta Regio, Atla Regio, Western Eistla Regio) show them to be distinct, having a range of volcanic and tectonic characteristics. In addition to these large areas, a number of smaller uplands are identified and are being analyzed (Bell Regio, Imdr Regio, Dione Regio (Ushas, Innini, and Hathor Montes), and Themis Regio). To understand better the mechanisms by which these volcanic rises form and evolve, we assess their geologic and geophysical characteristics.

Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

Directory of Open Access Journals (Sweden)

G. Fu

2016-07-01

Full Text Available The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

Research on petrologic, geochemical characteristics and genesis of volcanic rocks in Dachangsha basin

International Nuclear Information System (INIS)

Wei Sanyuan

1999-01-01

On the basis of research on petrologic, geochemical characteristics and isotope composition of volcanic rocks in Dachangsha basin, the author concludes that the volcanic rocks formed from magma of different genesis and depth are double-cycle effusive. It is proposed that the magma forming the intermediate-basic volcanics of the first cycle comes from the mixing of the partial melting of the deep crust and mantle, and the intermediate-acidic volcanics of the secondary cycle are derived from the remelting of the upper crust

Pseudotachylyte formation in volcanic conduits: Montserrat vs. Mount St. Helens

Science.gov (United States)

Kendrick, J. E.; Lavallee, Y.; Petrakova, L.; Ferk, A.; Di Toro, G.; Hess, K.; Ferri, F.; Dingwell, D. B.

2012-12-01

Seismogenic fracture and faulting may result in non-equilibrium frictional melting of rock, which upon cooling and recrystallisation forms pseudotachylyte. In volcanic environments, the transition from endogenous to exogenous growth can be attributed to a shift in magma rheology into the brittle regime, and thus the ascent of high-viscosity magma can form discrete shear zones, comparable to tectonic faults, along conduit margins. Pseudotachylytes have, until now, rarely been noted in exogenous volcanic materials and seldom in active volcanic environments. This is despite the simultaneous occurrence of high pressures and differential stresses, which make high-viscosity magmas ideal candidates for the occurrence of frictional melting. Here, we compare the chemical, thermal, magnetic and structural properties of two candidate volcanic pseudotachylytes; one from Soufriere Hills (Montserrat) and one from Mount St. Helens (USA). Additionally, we present data from a set of high-velocity rotary shear experiments on the host materials of these natural pseudotachylytes in which melting was induced after just 10's of centimeters of slip at realistic extrusion velocities (0.4 - 1.6 ms-1) and low normal stresses (0.5-2 MPa). After 1-2 meters of slip a continuous melt layer formed, at which point friction decreased and the fault zone displayed slip-weakening behaviour. For volcanic conduits, this would facilitate temporarily elevated slip rates, or an increase in extrusion rate, and could cause transitions in dome morphology and eruption style. This study demonstrates that shear fracturing in magma or sliding along conduit margins can readily result in frictional melting. The conspicuous absence of pseudotachylytes in active volcanic environments is likely the result of exceptionally high background temperatures which precipitate near-equilibrium melting, thereby obviating one of the characteristic signatures of pseudotachylyte - glassy protomelts formed by selective melting of

Comentarios sobre el artículo de Héctor Sauret: “El proyecto Puiggrós de Ley sobre Regulación del ejercicio de la docencia de la Educación Superior, entre viejos y nuevos paradigmas sobre las universidades privadas”

Directory of Open Access Journals (Sweden)

Juan Carlos Pugliese

2013-05-01

Full Text Available En el número 1 de DEBATE UNIVERSITARIO se debatió los proyectos de ley alternativos y diversas opiniones sobre la modificación del ejercicio de la docencia de la Educación Superior. Entre dichas opiniones se incluyó un artículo del Dr. Sauret : " El proyecto Puiggrós de Ley sobre Regulación del ejercicio de la docencia de la Educación Superior: entre viejos y nuevos paradigmas sobre las universidades privadas”. En referencia a este material (que puede consultarse en http://ppct.caicyt.gov.ar/index.php/debate-universitario/article/view/1606/pdf se desarrolla el siguiente comentario.

LA CIENCIA EN LA ACTIVIDAD FÍSICA: VIEJOS Y NUEVOS PROBLEMAS

Directory of Open Access Journals (Sweden)

A. Oña

2010-09-01

Full Text Available

RESUMEN

La relación entre el conocimiento científico y la actividad física ha recorrido una trayectoria histórica problemática. En este artículo tratamos de identificar las resistencias que han dificultado su integración, partiendo de cuatro problemas que consideramos básicos: Indefinición del Objeto de Estudio, Alejamiento del Conocimiento Científico, Marginalidad Institucional, y Artesanía Profesional. Después de definir los problemas, realizamos una revisión de la evolución del pensamiento occidental para constituir el dualismo cultural como el núcleo histórico latente que los ha originado y sustentado. Posteriormente, analizamos las características del conocimiento científico y la situación de la actividad física respecto de él, siguiendo las categorías de Kuhn (1975. A continuación, tratamos de identificar las claves del cambio social producido en el pensamiento sobre la actividad física en la dos últimas décadas, tanto en el nivel de los hábitos y actitudes de los ciudadanos como en el de la integración institucional en la universidad. Por último, realizamos una serie de propuestas para superar las resistencias que permanecen derivadas de los viejos problemas en la consolidación de la actividad física como área científica.
PALABRAS CLAVE: Ciencias Actividad Física, Explicaciones Actividad Física, Objeto Estudio, Conocimiento Científico, Situación Institucional

ABSTRACT

The relationship between scientific knowledge and physical activity has had a problematical historical trajectory. In this paper we tried to identify the obstacles that have made the integration of both fields difficult. We

Collateral variations between the concentrations of mercury and other water soluble ions in volcanic ash samples and volcanic activity during the 2014-2016 eruptive episodes at Aso volcano, Japan

Science.gov (United States)

Marumoto, Kohji; Sudo, Yasuaki; Nagamatsu, Yoshizumi

2017-07-01

During 2014-2016, the Aso volcano, located in the center of the Kyushu Islands, Japan, erupted and emitted large amounts of volcanic gases and ash. Two episodes of the eruption were observed; firstly Strombolian magmatic eruptive episodes from 25 November 2014 to the middle of May 2015, and secondly phreatomagmatic and phreatic eruptive episodes from September 2015 to February 2016. Bulk chemical analyses on total mercury (Hg) and major ions in water soluble fraction in volcanic ash fall samples were conducted. During the Strombolian magmatic eruptive episodes, total Hg concentrations averaged 1.69 ± 0.87 ng g- 1 (N = 33), with a range from 0.47 to 3.8 ng g- 1. In addition, the temporal variation of total Hg concentrations in volcanic ash varied with the amplitude change of seismic signals. In the Aso volcano, the volcanic tremors are always observed during eruptive stages and quiet interludes, and the amplitudes of tremors increase at eruptive stages. So, the temporal variation of total Hg concentrations could provide an indication of the level of volcanic activity. During the phreatomagmatic and phreatic eruptive episodes, on the other hand, total Hg concentrations in the volcanic ash fall samples averaged 220 ± 88 ng g- 1 (N = 5), corresponding to 100 times higher than those during the Strombolian eruptive episode. Therefore, it is possible that total Hg concentrations in volcanic ash samples are largely varied depending on the eruptive type. In addition, the ash fall amounts were also largely different among the two eruptive episodes. This can be also one of the factors controlling Hg concentrations in volcanic ash.

Evidence for young volcanism on Mercury from the third MESSENGER flyby.

Science.gov (United States)

Prockter, Louise M; Ernst, Carolyn M; Denevi, Brett W; Chapman, Clark R; Head, James W; Fassett, Caleb I; Merline, William J; Solomon, Sean C; Watters, Thomas R; Strom, Robert G; Cremonese, Gabriele; Marchi, Simone; Massironi, Matteo

2010-08-06

During its first two flybys of Mercury, the MESSENGER spacecraft acquired images confirming that pervasive volcanism occurred early in the planet's history. MESSENGER's third Mercury flyby revealed a 290-kilometer-diameter peak-ring impact basin, among the youngest basins yet seen, having an inner floor filled with spectrally distinct smooth plains. These plains are sparsely cratered, postdate the formation of the basin, apparently formed from material that once flowed across the surface, and are therefore interpreted to be volcanic in origin. An irregular depression surrounded by a halo of bright deposits northeast of the basin marks a candidate explosive volcanic vent larger than any previously identified on Mercury. Volcanism on the planet thus spanned a considerable duration, perhaps extending well into the second half of solar system history.

Influence of mesostasis in volcanic rocks on the alkali-aggregate reaction

KAUST Repository

Tiecher, Francieli

2012-11-01

Mesostasis material present in the interstices of volcanic rocks is the main cause of the alkali-aggregate reaction (AAR) in concretes made with these rock aggregates. Mesostasis often is referred to as volcanic glass, because it has amorphous features when analyzed by optical microscopy. However, this study demonstrates that mesostasis in the interstitials of volcanic rocks most often consists of micro to cryptocrystalline mineral phases of quartz, feldspars, and clays. Mesostasis has been identified as having different characteristics, and, thus, this new characterization calls for a re-evaluation of their influence on the reactivity of the volcanic rocks. The main purpose of this study is to correlate the characteristics of mesostasis with the AAR in mortar bars containing basalts and rhyolites. © 2012 Elsevier Ltd. All rights reserved.

Influence of mesostasis in volcanic rocks on the alkali-aggregate reaction

KAUST Repository

Tiecher, Francieli; Dal Molin, Denise Carpena Coitinho; Gomes, Má rcia Elisa Boscato; Hasparyk, Nicole Pagan; Monteiro, Paulo José Meleragno

2012-01-01

Mesostasis material present in the interstices of volcanic rocks is the main cause of the alkali-aggregate reaction (AAR) in concretes made with these rock aggregates. Mesostasis often is referred to as volcanic glass, because it has amorphous features when analyzed by optical microscopy. However, this study demonstrates that mesostasis in the interstitials of volcanic rocks most often consists of micro to cryptocrystalline mineral phases of quartz, feldspars, and clays. Mesostasis has been identified as having different characteristics, and, thus, this new characterization calls for a re-evaluation of their influence on the reactivity of the volcanic rocks. The main purpose of this study is to correlate the characteristics of mesostasis with the AAR in mortar bars containing basalts and rhyolites. © 2012 Elsevier Ltd. All rights reserved.

Monitoramento de interações farmacocinéticas entre plantas medicinais e fitoterápicos e os medicamentos convencionais pelo sistema de farmacovigilância brasileiro

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André Luís Dias Araujo MAZZARI

2014-12-01

Full Text Available O consumo de plantas medicinais e fitoterápicos está cada vez mais em expansão pelo mundo. Contudo, os fitoterápicos, como qualquer xenobiótico, podem causar alterações farmacocinéticas no organismo, ocasionando distúrbios nos metabolismos de fase 1 e fase 2, devido à inibição ou indução de enzimas metabólicas. Em caso de coadministração de plantas medicinais e/ou fitoterápicos com medicamentos convencionais, poderá haver interações que comprometem a eficácia do último, ocasionando uma falha terapêutica. Como ensaios pré-clínicos farmacocinéticos não são uma exigência regulatória para que um medicamento fitoterápico seja registrado, os casos de interações com fármacos convencionais (Herb-Drug Interactions - HDI acabam sendo revelados somente na fase de pós- -comercialização, ou seja, pelos sistemas de farmacovigilância. Inúmeros países já reportaram casos de HDI através de seus respectivos centros de farmacovigilância à Organização Mundial de Saúde (OMS, mas até o momento, o Brasil não reportou nenhum oficialmente. Além disso, durante os primeiros 10 anos de monitoramento, nenhum caso de HDI envolvendo plantas medicinais brasileiras foi apresentado. Sabe-se que aproximadamente 90% da população brasileira fazem uso de plantas medicinais e fitoterápicos, e que casos de HDI podem estar acontecendo sem serem percebidos e/ou notificados. Para que este cenário mude, é necessário que se adote medidas que visem ao estímulo do profissional de saúde à comunicação de suspeita de HDI para o centro de farmacovigilância, bem como a educação continuada destes profissionais, com a inclusão de especialistas em medicina tradicional no sistema de saúde, além de campanhas de prevenção à automedicação de plantas medicinais e fitoterápicos pela população, que atualmente não é praticado no Brasil.

Prototype of a hybrid cosmic ray detector at the Pico de Orizaba: First stage

International Nuclear Information System (INIS)

Ponce, E.; Perez, E.; Villasenor, L.; Garipov, G.; Salazar, H.; Martinez, O.; Moreno, E.; Pedraza, I.; Cotzomi, J.; Khrenov, B.

2003-01-01

In this work we present a progress report of the project of a high energy cosmic ray observatory located at Pico de Orizaba mountain. One of the goals of this facility will be to contribute to the understanding of the origin of the cosmic rays at energies around the feature known as the knee. To achieve this goal we plan to use a hybrid detector composed of a surface detector array and a fluorescence telescope. The design and expected performance of the fluorescent detector is presented

Exploring Geology on the World-Wide Web--Volcanoes and Volcanism.

Science.gov (United States)

Schimmrich, Steven Henry; Gore, Pamela J. W.

1996-01-01

Focuses on sites on the World Wide Web that offer information about volcanoes. Web sites are classified into areas of Global Volcano Information, Volcanoes in Hawaii, Volcanoes in Alaska, Volcanoes in the Cascades, European and Icelandic Volcanoes, Extraterrestrial Volcanism, Volcanic Ash and Weather, and Volcano Resource Directories. Suggestions…

Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua

Science.gov (United States)

Pearson, S.C.P.; Connor, C.B.; Sanford, W.E.

2008-01-01

Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active volcanoes in Central America. The soil temperatures were measured in a low-temperature fumarole field located 3.5 km down the flanks of the volcano. Analysis of these time series reveals that they respond extremely rapidly, on a time scale of minutes, to changes in volcanic activity also manifested at the summit vent. These rapid temperature changes are caused by increased flow of water vapor through flank fumaroles during volcanism. The soil temperature response, ~5 °C, is repetitive and complex, with as many as 13 pulses during a single volcanic episode. Analysis of the frequency spectrum of these temperature time series shows that these anomalies are characterized by broad frequency content during volcanic activity. They are thus easily distinguished from seasonal trends, diurnal variations, or individual rainfall events, which triggered rapid transient increases in temperature during 5% of events. We suggest that the mechanism responsible for the distinctive temperature signals is rapid change in pore pressure in response to magmatism, a response that can be enhanced by meteoric water infiltration. Monitoring of distal fumaroles can therefore provide insight into coupled volcanic-hydrologic-meteorologic systems, and has potential as an inexpensive monitoring tool.

Volcanic glass signatures in spectroscopic survey of newly proposed lunar pyroclastic deposits

Science.gov (United States)

Besse, S.; Sunshine, J.M.; Gaddis, L.R.

2014-01-01

Moon Mineralogy Mapper spectroscopic observations are used to assess the mineralogy of five sites that have recently been proposed to include lunar dark mantle deposits (DMDs). Volcanic glasses have, for the first time, clearly been identified at the location of three of the proposed pyroclastic deposits. This is the first time that volcanic glasses have been identified at such a small scale on the lunar surface from remote sensing observations. Deposits at Birt E, Schluter, and Walther A appear to be glassy DMDs. Deposits at Birt E and Schluter show (1) morphological evidence suggesting a likely vent and (2) mineralogical evidence indicative of the presence of volcanic glasses. The Walther A deposits, although they show no morphological evidence of vents, have the spectroscopic characteristics diagnostic of volcanic glasses. The deposits of the Freundlich-Sharonov basin are separated in two areas: (1) the Buys-Ballot deposits lack mineralogical and morphological evidence and thus are found to be associated with mare volcanism not with DMDs and (2) the Anderson crater deposits, which do not exhibit glassy DMD signatures, but they appear to be associated with possible vent structures and so may be classifiable as DMDs. Finally, dark deposits near the crater Kopff are found to be associated with likely mare volcanism and not associated with DMDs. The spectral identification of volcanic glass seen in many of the potential DMDs is a strong indicator of their pyroclastic origin.

Depleted arc volcanism in the Alboran Sea and shoshonitic volcanism in Morocco: geochemical and isotopic constraints on Neogene tectonic processes

Science.gov (United States)

Gill, R. C. O.; Aparicio, A.; El Azzouzi, M.; Hernandez, J.; Thirlwall, M. F.; Bourgois, J.; Marriner, G. F.

2004-12-01

Samples of volcanic rocks from Alborán Island, the Alboran Sea floor and from the Gourougou volcanic centre in northern Morocco have been analyzed for major and trace elements and Sr-Nd isotopes to test current theories on the tectonic geodynamic evolution of the Alboran Sea. The Alborán Island samples are low-K tholeiitic basaltic andesites whose depleted contents of HFS elements (˜0.5×N-MORB), especially Nb (˜0.2×N-MORB), show marked geochemical parallels with volcanics from immature intra-oceanic arcs and back-arc basins. Several of the submarine samples have similar compositions, one showing low-Ca boninite affinity. 143Nd/ 144Nd ratios fall in the same range as many island-arc and back-arc basin samples, whereas 87Sr/ 86Sr ratios (on leached samples) are somewhat more radiogenic. Our data point to active subduction taking place beneath the Alboran region in Miocene times, and imply the presence of an associated back-arc spreading centre. Our sea floor suite includes a few more evolved dacite and rhyolite samples with ( 87Sr/ 86Sr) 0 up to 0.717 that probably represent varying degrees of crustal melting. The shoshonite and high-K basaltic andesite lavas from Gourougou have comparable normalized incompatible-element enrichment diagrams and Ce/Y ratios to shoshonitic volcanics from oceanic island arcs, though they have less pronounced Nb deficits. They are much less LIL- and LREE-enriched than continental arc analogues and post-collisional shoshonites from Tibet. The magmas probably originated by melting in subcontinental lithospheric mantle that had experienced negligible subduction input. Sr-Nd isotope compositions point to significant crustal contamination which appears to account for the small Nb anomalies. The unmistakable supra-subduction zone (SSZ) signature shown by our Alboran basalts and basaltic andesite samples refutes geodynamic models that attribute all Neogene volcanism in the Alboran domain to decompression melting of upwelling asthenosphere

Fault propagation folds induced by gravitational failure and slumping of the Central Costa Rica volcanic range: Implications for large terrestrial and Martian volcanic edifices

International Nuclear Information System (INIS)

Borgia, A.; Burr, J.; Montero, W.; Morales, L.D.; Alvarado, G.E.

1990-01-01

Long sublinear ridges and related scarps located at the base of large volcanic structures are frequently interpreted as normal faults associated with extensional regional stress. In contrast, the ridges bordering the Central Costa Rica volcanic range (CCRVR) are the topographic expression of hanging wall asymmetric angular anticlines overlying low-angle thrust faults at the base of the range. These faults formed by gravitational failure and slumping of the flanks of the range due to the weight of the volcanic edifices and were perhaps triggered by the intrusion of magma over the past 20,000 years. These anticlines are hypothesized to occur along the base of the volcano, where the thrust faults ramp up toward the sea bottom. Ridges and scarps between 2,000 and 5,000 m below sea level are interpreted as the topographic expression of these folds. The authors further suggest that the scarps of the CCRVR and valid scaled terrestrial analogs of the perimeter scarp of the Martian volcano Olympus Mons. They suggest that the crust below Olympus Mons has failed under the load of the volcano, triggering the radial slumping of the flanks of the volcano on basal thrusts. The thrusting would have, in turn, formed the anticlinal ridges and scarps that surround the edifice. The thrust faults may extend all the way to the base of the Martian crust (about 40 km), and they may have been active until almost the end of the volcanic activity. They suggest that gravitational failure and slumping of the flanks of volcanoes is a process common to most large volcanic edifices. In the CCRVR this slumping of the flanks is a slow intermittent process, but it could evolve to rapid massive avalanching leading to catastrophic eruptions. Thus monitoring of uplift and displacement of the folds related to the slump tectonics could become an additional effective method for mitigating volcanic hazards

Role of crustal assimilation and basement compositions in the petrogenesis of differentiated intraplate volcanic rocks: a case study from the Siebengebirge Volcanic Field, Germany

Science.gov (United States)

Schneider, K. P.; Kirchenbaur, M.; Fonseca, R. O. C.; Kasper, H. U.; Münker, C.; Froitzheim, N.

2016-06-01

The Siebengebirge Volcanic Field (SVF) in western Germany is part of the Cenozoic Central European Volcanic Province. Amongst these volcanic fields, the relatively small SVF comprises the entire range from silica-undersaturated mafic lavas to both silica-undersaturated and silica-saturated differentiated lavas. Owing to this circumstance, the SVF represents a valuable study area representative of intraplate volcanism in Europe. Compositions of the felsic lavas can shed some new light on differentiation of intraplate magmas and on the extent and composition of potential crustal assimilation processes. In this study, we provide detailed petrographic and geochemical data for various differentiated SVF lavas, including major and trace element concentrations as well as Sr-Nd-Hf-Pb isotope compositions. Samples include tephriphonolites, latites, and trachytes with SiO2 contents ranging between 53 and 66 wt%. If compared to previously published compositions of mafic SVF lavas, relatively unradiogenic 143Nd/144Nd and 176Hf/177Hf coupled with radiogenic 87Sr/86Sr and 207Pb/204Pb lead to the interpretation that the differentiated volcanic rocks have assimilated significant amounts of lower crustal mafic granulites like the ones found as xenoliths in the nearby Eifel volcanic field. These crustal contaminants should possess unradiogenic 143Nd/144Nd and 176Hf/177Hf, radiogenic 87Sr/86Sr, and highly radiogenic 207Pb/204Pb compositions requiring the presence of ancient components in the central European lower crust that are not sampled on the surface. Using energy-constrained assimilation-fractional crystallisation (EC-AFC) model calculations, differentiation of the SVF lithologies can be modelled by approximately 39-47 % fractional crystallisation and 6-15 % crustal assimilation. Notably, the transition from silica-undersaturated to silica-saturated compositions of many felsic lavas in the SVF that is difficult to account for in closed-system models is also well explained by

Presença do pensamento utópico nos romances de Lima Barreto

OpenAIRE

Alice Atsuko Matsuda

2009-01-01

A presente tese teve como objetivo verificar como se configurou o pensamento utópico nos romances de Lima Barreto. Os romances analisados foram: Recordações do escrivão Isaías Caminha (1909), Triste fim de Policarpo Quaresma (1911 em folhetim e 1916 em livro), Numa e a ninfa (1915 em folhetim e 1917 em livro), Vida e morte de M. J. Gonzaga de Sá (1919), Clara dos Anjos (1948 – publicação póstuma). Partiu-se do pressuposto de que o romancista tinha uma postura de um romantismo revolucionário o...

Enhanced ice sheet melting driven by volcanic eruptions during the last deglaciation.

Science.gov (United States)

Muschitiello, Francesco; Pausata, Francesco S R; Lea, James M; Mair, Douglas W F; Wohlfarth, Barbara

2017-10-24

Volcanic eruptions can impact the mass balance of ice sheets through changes in climate and the radiative properties of the ice. Yet, empirical evidence highlighting the sensitivity of ancient ice sheets to volcanism is scarce. Here we present an exceptionally well-dated annual glacial varve chronology recording the melting history of the Fennoscandian Ice Sheet at the end of the last deglaciation (∼13,200-12,000 years ago). Our data indicate that abrupt ice melting events coincide with volcanogenic aerosol emissions recorded in Greenland ice cores. We suggest that enhanced ice sheet runoff is primarily associated with albedo effects due to deposition of ash sourced from high-latitude volcanic eruptions. Climate and snowpack mass-balance simulations show evidence for enhanced ice sheet runoff under volcanically forced conditions despite atmospheric cooling. The sensitivity of past ice sheets to volcanic ashfall highlights the need for an accurate coupling between atmosphere and ice sheet components in climate models.

Total Volcanic Stratospheric Aerosol Optical Depths and Implications for Global Climate Change

Science.gov (United States)

Ridley, D. A.; Solomon, S.; Barnes, J. E.; Burlakov, V. D.; Deshler, T.; Dolgii, S. I.; Herber, A. B.; Nagai, T.; Neely, R. R., III; Nevzorov, A. V.;

Bases científicas de la terapia de conducta: nuevas propuestas para un viejo problema

Directory of Open Access Journals (Sweden)

Xavier Bornas

2002-01-01

Full Text Available En este trabajo se revisa críticamente el recurrente tópico de las bases científicas de la Terapia de Conducta. Asumiendo que la investigación científica de la conducta es conveniente, si no necesaria, para el desarrollo tecnológico y aplicado, se propone tomar en consideración algunos conceptos relativamente nuevos de la Ciencia (por ejemplo, el de caos determinístico y utilizarlos, al menos tentativamente, para procurar obtener un conocimiento mejor de la complejidad de la conducta humana. La incorporación de aquellos conceptos abre una nueva perspectiva complementaria para el estudio de la conducta que se caracteriza por: (a conceder una importancia capital al cambio o flujo continuo de conducta y los procesos de retroalimentación del sistema, (b destacar, además de las relaciones lineales, las de tipo no lineal entre la conducta y el ambiente, y (c tener en cuenta la emergencia de nuevos patrones de comportamiento. Se discute también la necesidad de la investigación de laboratorio y el análisis de los datos así obtenidos.

Volcanic eruptions are cooling the earth

International Nuclear Information System (INIS)

Groenaas, Sigbjoern

2005-01-01

The article discusses how volcanic eruptions may influence the climate. The environmental impacts both on the earth surface and the atmosphere are surveyed. Some major eruptions in modern times are mentioned

Rapid laccolith intrusion driven by explosive volcanic eruption.

Science.gov (United States)

Castro, Jonathan M; Cordonnier, Benoit; Schipper, C Ian; Tuffen, Hugh; Baumann, Tobias S; Feisel, Yves

2016-11-23

Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km 3 . Deformation and conduit flow models indicate laccolith depths of only ∼20-200 m and overpressures (∼1-10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards.